(Circulation. 1995;92:2343-2351.)
© 1995 American Heart Association, Inc.
Articles |
Distribution, Morphology, and Neurochemistry of Endocardial and Epicardial Nerve Terminal Arborizations in the Human Heart
From the Department of Histochemistry, Royal Postgraduate Medical School, London, England (K.M., J.W., J.M.P.); Department of Pathology, Queen's Medical Centre, Nottingham, England (D.F.); Department of Pathology, Beaumont Hospital, Dublin, Ireland (D.R.); Laboratory of Neurochemistry, Lafayette Clinic, Detroit, Mich (D.M.K.); Cardiothoracic Surgery Unit, Great Ormond Street Hospital for Children, London, England (M.R. de L.); and Departments of Pathology (M.N.S.) and Paediatric Cardiology (K.M., R.H.A.), National Heart and Lung Institute, London, England.
Correspondence to Dr John Wharton, Department of Histochemistry, Royal Postgraduate Medical School, Du Cane Rd, London W12 ONN, UK.
 |
Abstract |
|---|
 Top Abstract IntroductionMethods Results Discussion References |
|---|
Background The heart contains a variety of morphologically distinct nerve terminals known to influence cardiac function. Little is known about the distribution, morphology, and neurochemistry of these terminals in the human heart.
Methods and Results We examined the entire endocardial and epicardial surfaces of infant and adult hearts obtained postmortem and at transplantation using immunohistochemical and histochemical staining of whole-mount preparations in conjunction with confocal and fluorescence microscopy. Terminals arising from nerve fibers (diameter, 6 to 10 µm) immunoreactive for myelin basic protein were identified in the atrial endocardium, epicardium, and coronary sinus, and four types were distinguished by differences in immunostained nerve area (range, 358 to 797 µm2) and dispersion (range, 620 to 4684 µm2). These terminals displayed immunoreactivity for tyrosine hydroxylase, neuropeptide Y, and the general neural marker protein gene product 9.5. Acetylcholinesterase (AChE) activity was detected in <5% of endocardial terminals and in no epicardial terminals arising from myelinated fibers. The latter were observed in close proximity to mesothelial cells, and nerve fibers supplying these terminals were found to be associated with local ganglia. A distinct population of terminals (mean stained area, 35 µm2; 18 to 53 µm2, 95% CI; and mean dispersion, 59 µm2; 38 to 80 µm2, 95% CI) was demonstrated to arise from nonmyelinated fibers (mean diameter, 2.5 µm; 2.2 to 2.8 µm, 95% CI) in the endocardial plexus of the atria and left ventricle and were predominantly AChE-positive.
Conclusions Specialized nerve terminals are distributed more widely in the human heart than has been described in experimental animals. These terminals express either AChE activity or tyrosine hydroxylase and neuropeptide Y immunoreactivity, suggesting that acetylcholine, catecholamines, and neuropeptide Y may be present in sensory and autonomic nerves in the human heart.
Key Words: endocardium • nervous system • receptors • peptides • endothelium
|
Introduction |
|---|
|
TopAbstractIntroductionMethods Results Discussion References |
|---|
The presence of receptors in the heart that affect the circulatory system was suggested by Von Bezold and Hirt in 1867 after they observed the depressor effects elicited by the injection into the heart of Veratrum alkaloids and the prevention of this effect by bilateral vagotomy.1 The functions of the terminal receptors within the heart, however, are still poorly understood. In humans, in particular, very little is known about their distribution, morphology, and neurochemistry.
The first morphological studies that localized the cardiac receptors are attributed to Berkeley and Smirnow, who both described specialized nerve terminal arborizations in the atrial endocardium of dogs and cats by use of silver staining and methylene blue infusion-perfusion techniques.2 These findings were confirmed over many years by other investigators using various mammals.2 Jarish and Zotterman3 were the first to apply physiological and electrophysiological techniques to detect cardiac receptors. They described activity in slow-conducting vagal afferents from the ventricles that were responsive to mechanical stimulation and Veratrum alkaloids. Since then, several distinct groups of receptors within mammalian atria and ventricles have been demonstrated on the basis of conduction velocities and afferent nerve origin. These comprise receptors that discharge into myelinated afferent fibers in the cervical vagi,4 nonmyelinated afferent fibers in the vagi,5 and the sympathetic nerves.6 The nerve terminals were first classified morphologically by Miller and Kasahara,7 who distinguished between several types of nerve terminals, which were considered, in light of electrophysiological4 and physiological8 reports and the relatively large diameter of the supplying nerve fiber, to represent myelinated afferents.9 Principal among these are the complex unencapsulated endings generally found at the atriovenous junctions and formed by repeated branching of discrete nerve terminals to give an elaborate arborization. A further type, known as an end net or terminal reticulum, was also identified and is the least distinct of the mammalian cardiac nerve terminals; it is represented by free fiber endings that may show some branching. Controversy remains over the existence of these latter structures and whether they have a sensory function.7 10
Therefore, the aim of this study was to establish and clarify the diverse morphology and distribution of nerve terminal arborizations in the human heart and to investigate the expression of neuropeptides and other neuronal markers. The relation of nerve terminals to intrinsic ganglia, the endocardial plexus, and endocardial endothelial and epicardial mesothelial cells also was assessed.
|
Methods |
|---|
|
TopAbstractIntroductionMethods Results Discussion References |
|---|
Tissue Processing
Human atrial and ventricular endocardium and epicardium, including the atriovenous connections and the coronary sinus, were obtained postmortem (2 to 24 hours after death) from 8 complete adult and infant hearts (Table 1
). Two
other hearts were obtained at transplantation
from 1 child and 1 adolescent with cystic fibrosis. Incomplete atrial
and ventricular tissue samples from specific areas within
the heart, including the free walls, septum, atrial roof, and
appendage, were taken from 7 additional hearts postmortem (Table
1).
All tissues were fixed for 16 to 36 hours at 4°C by immersion in
modified Bouin's solution, and whole-mount preparations were
dissected and processed for indirect
immunofluorescence and demonstration of
acetylcholinesterase (AChE) activity as described
previously.11 The entire endocardium and atrial
epicardium, including atriovenous connections and coronary
sinus, were sampled in all hearts, and the entire
ventricular epicardium was sampled in four cases. The
epicardial layers and the coronary sinus were processed as
intact whole-mount preparations; the endocardium required further
microdissection from underlying connective tissue before staining. The
endocardium and coronary sinus whole-mount preparations
were approximately 5 mm2 in area, whereas the atrial
epicardial whole mounts averaged 15 mm2. Eight to 10
whole-mount preparations per antigen were taken from both the
endocardial and epicardial surfaces of each chamber. As demonstrated
previously,11 no significant stretching or shrinkage was
found during the staining and mounting of the preparations.
|
Immunofluoresence and AChE Staining
Whole-mount preparations
were incubated in PBS containing
0.2% Triton X-100 for 16 to 24 hours at room temperature and
impregnated with Pontamine sky blue.11 After incubation in
normal goat antiserum (1:20 dilution) for 30 minutes and in diluted
primary antisera (Table 2) for 16 to 24 hours at room
temperature, the preparations were washed several times in PBS and
incubated for 60 minutes in FITC-conjugated goat anti-rabbit IgG
(1:100 dilution, Tago Inc). After further washing in PBS and distilled
water, the endocardium and coronary sinus preparations were
oriented endothelial side up, and the epicardium
preparations were oriented mesothelial side up on glass slides and
mounted with Vectashield (Vector Laboratories Ltd). All negative
preparations were refloated in PBS and incubated in primary antiserum
to the general neural marker protein gene product 9.5 (PGP-9.5) to
allow the positions of all cardiac nerve terminal arborizations to be
visualized and recorded. Controls included omission of the primary
antisera, use of inappropriate secondary antisera, and preabsorption
with their respective antigens (10-5 to 10-6
mol/L) for 2 hours at room temperature, which prevented
immunostaining. Double immunostaining
of tyrosine hydroxylase and neuropeptide Y nerve subpopulations was
achieved by sequential addition of antisera to neuropeptide Y,
TRITC-labeled goat anti-rabbit IgG, antisera to tyrosine
hydroxylase raised in sheep (Table 2), and FITC-labeled donkey
anti-sheep IgG (Chemicon International Ltd).
|
AChE-positive nerve terminals were demonstrated as described previously.11 Negative controls included incubation of preparations without acetylthiocholine iodide and in the presence of 10-4 mol/L eserine.
Multiple Staining by Acid Elution
Acid elution of antibody
complexes was used for sequential
visualization of neural markers.19 Whole-mount
preparations, with previously photographed immunostained
nerve terminals, were immersed in an aqueous solution containing 1 vol
2.5% KMnO4, 1 vol 5%
H2SO4, and 50 vol distilled water. The
immersion time ranged from 8 to 15 minutes and was dependent on
preparation thickness and the avidity of the antibody for its antigen.
This treatment resulted in denaturation of the previously applied
antibody complex without concomitant effects on subsequent
immunostaining. The preparations were briefly destained
in 0.5% Na2S2O5 (Sigma Chemical
Co), washed several times in distilled water, and incubated with
primary antiserum to myelin basic protein or other neural antigens
(Table 2
). Controls included reapplication of FITC-labeled goat
anti-rabbit IgG after acid elution to confirm complete denaturation
of antibody-antigen complexes and reapplication of the original or
application of another neural marker after sequential visualization of
immunoreactivity to confirm that the terminal arborization was
undamaged.
Quantitative Analysis of Nerve Terminals and Laser Scanning
Confocal Microscopy
The immunostained nerve area and the area occupied
by nerve terminal processes were determined by computer-assisted
analysis of immunofluorescent and AChE-positive
images by a Kontron 386 image processing system (Kontron Elektronik
Ltd). The captured images were digitized into a 512x768 pixel array,
with each pixel representing one of 256 gray levels. The
terminal arborization was interactively discriminated, and the
immunostained nerve area occupied by each terminal and the
diameter of the supplying nerve fiber were measured (Table 3).
|
To obtain a single focused image of the immunostained nerve terminals and their associated nerve fibers, whole-mount preparations were examined with a confocal microscope (Bio-Rad MRC-600, Bio-Rad Microscience Division). Immunostained nerve terminals were visualized by use of x10 or x20 objectives linked to a variable software zoom (x1.2 to x2.0), and images were captured at 1.0-µmol/L increments through the preparation by use of a motorized microscope stage. Individual images were stored in sequence and projected together to reconstruct the entire three-dimensional structure as a single image. This incremental data also provided an assessment of the relation between nerve terminal arborizations, the supplying nerve fibers, intrinsic ganglia, the endocardial plexus, and the overlying endothelial or epicardial mesothelial cells. Dual-channel confocal microscopy11 also was used to assess colocalization in double-immunostained nerve fibers.
|
Results |
|---|
|
TopAbstractIntroductionMethods Results Discussion References |
|---|
Morphology and Distribution of Endocardial Nerve Terminals
Using antisera to the general neural marker PGP-9.5, we identified three types of morphologically distinct nerve terminal in the endocardium (Fig 1
, Table 3). Two principal
types were
identified in the atrial endocardium that were preferentially
associated with the cavoatrial junctions and the endocardial vestibules
above the mitral and tricuspid valvar orifices (Figs 2 and
3). Both types were found more frequently in the
left than in the right atrium. These terminals could be distinguished
on the basis of the area occupied by their terminal arborization. One
type (Fig 2, Table 3) extended over an area
approximately three times
greater than that of the other (Fig 3, Table 3),
and similar nerve
terminals were identified in the endocardium lining the
coronary sinus (Figs 1 and 4, Table
3). All of
these terminals arose from individual, predominantly nonvaricose, and
relatively thick fibers (6 to 7 µm in diameter) that displayed
immunoreactivity for myelin basic protein (Fig 5A and
5C, Table 3). These nerves were traced over
several centimeters
and appeared to be separate from the endocardial plexus. The
arborizations themselves were also localized to discrete areas in which
the endocardial plexus was generally absent.
|
, 
) or
nonmyelinated (*) nerve fibers, the former being
subdivided into terminals occupying a relatively large (
) were identified only as arising
from myelinated nerves. Ao indicates aorta; RA, right
atrium; PT, pulmonary trunk; RV, right ventricle; LAD, left
anterior descending coronary artery; LA, left atrium; LV, left
ventricle, CS, coronary sinus; and dashed lines, approximate
positions of AV valves.
|
|
|
|
The third type of
endocardial nerve terminal had several distinct
morphological features that set it apart from those described above and
was the only type found in the ventricular endocardium.
These nerve terminals were relatively small and were associated with
nonmyelinated, nonvaricose nerve fibers of the
endocardial plexus (Fig 6, Table 3). They
occurred in
groups rather than as individual endings and were numerous in such
areas as the roof of the left atrium and lateral wall of the right
atrium. In the left ventricle, they showed a preferential localization
to the endocardium lining the papillary muscles (Figs 1 and
6). No
nerve terminals were found in the endocardium of the right
ventricle.
|
Neurochemistry of the Endocardial Nerve Terminals
Most of the
nerve terminals in the endocardium and
coronary sinus arising from myelin basic
protein–immunoreactive fibers exhibited immunoreactivity for
tyrosine hydroxylase and neuropeptide Y (Figs 2 through
5). Less than
5% of the PGP-9.5–immunoreactive terminals identified displayed AChE
reactivity (Figs 2 and 3). Nerve terminals
demonstrated in the
coronary sinus were also immunoreactive for tyrosine
hydroxylase, neuropeptide Y, and PGP-9.5, but none displayed AChE
activity. In contrast, the terminals served by
nonmyelinated nerves were predominantly AChE-positive,
and relatively few were shown to be either tyrosine hydroxylase–,
neuropeptide Y–, or somatostatin-immunoreactive (Fig 6).
Sequential staining of the same preparation demonstrated that
AChE-positive nerves were distinct from those displaying neuropeptide Y
and tyrosine hydroxylase immunoreactivity. No endocardial or
coronary sinus nerve terminals or their associated fibers
displayed immunoreactivity for vasoactive intestinal polypeptide,
calcitonin gene–related peptide, or substance P, although
immunoreactivity for these peptides was localized to nerve fibers in
the endocardial plexus and epicardium.
Morphology and Distribution of Epicardial Nerve
Terminals
PGP-9.5–immunoreactive nerve terminals were localized
to the
atrial epicardium (Figs 1 and 7) and, to a
lesser
extent, the left ventricular epicardium (Fig 1). None were
found in the epicardium covering the right ventricle. All epicardial
terminals arose from individual myelinated nerve fibers
(Fig 5B and 5D, Table 3); some
were traced back to nerve fascicles
associated with local ganglia displaying PGP-9.5 immunoreactivity (Fig
8). The epicardial terminals were localized
preferentially to both sides of the atrial appendages and, to a lesser
extent, the epicardial surface of the superior caval and
pulmonary veins (Fig 1). Like their endocardial counterparts,
these terminals were considerably more numerous in the left compared
with the right atrial epicardium and occasionally arose in groups from
one or more nerve fibers (Fig 7E and 7F). The
epicardial terminals were
localized predominantly in the connective tissue below the mesothelial
cell layer, but some terminals were observed with fibers running
between these cells (Fig 9A, Table 3).
|
|
|
Neurochemistry of the Epicardial Nerve Terminals
The
epicardial terminals displayed immunoreactivity for tyrosine
hydroxylase and neuropeptide Y (Fig 7C, 7D, and
7F). No nerve terminals
were found to display AChE activity or immunoreactivity for substance
P, calcitonin gene–related peptide, vasoactive intestinal
polypeptide, and somatostatin. Tyrosine hydroxylase immunoreactivity
was detected in ganglion cell bodies in the epicardium of
3-month-old infant hearts (Fig 9B) but not at later stages of
development, and no peptide immunoreactivity was demonstrated.
Immunoreactivities for neuropeptide Y and tyrosine hydroxylase were
found to be colocalized in nerve fibers, fascicles, and terminals in
both endocardial and epicardial whole-mount preparations (Fig
10).
|
No differences were found in the distribution, morphology, and neurochemistry of the cardiac nerve terminals among normal tissue, tissue from hearts of infants and adults who died suddenly, and tissue from hearts obtained either postmortem or at surgery. Negative staining for AChE activity in nerve terminals in the atrial epicardium, coronary sinus, and ventricular endocardium was not due to diffusion of chromogen. This may be observed when preparations are not dehydrated; in this study, however, all preparations were dehydrated and mounted in nonaqueous medium immediately after staining for AChE activity. In addition, AChE activity was demonstrated in nerve fibers and fascicles in regions devoid of AChE-positive terminals.
|
Discussion |
|---|
|
TopAbstractIntroductionMethods Results Discussion References |
|---|
We identified endocardial nerve terminals in the hearts of both infants and adults that could be correlated, both in distribution and morphology, with those described in extensive anatomic studies of various mammals.2 Significant differences were also demonstrated. Thus, the human endocardium does not appear to contain nerve terminal arborizations supplied by myelinated nerves in the pulmonary or aortic outflow tract, as reported in some species, nor in the mouth of the coronary sinus.2 One finding that, to the best of our knowledge, has not been made in other mammals is the localization of terminals within the lumen of the coronary sinus, in the atrial and left ventricular epicardium, and arising from nonmyelinated nerves in the endocardial plexus.
Endocardial and Epicardial Nerve Terminals Served by
Myelinated Nerves
Endocardial receptors served by myelinated
nerves are believed to be involved in the monitoring and control of
heart rate,20 atrial filling,21 and central
venous pressure.22 Because of the lack of direct
physiological information in either animals or
humans concerning the epicardial receptors, we can only speculate as to
their function. Given their corresponding localization to that in the
endocardium, the epicardial receptors may be responsible in part for
many of the reflex effects hitherto attributed to the endocardial
terminals. Unlike those in the endocardium, the epicardial
terminals also displayed an association with epicardial mesothelial
cells. Recent observations suggest that prostaglandins and
other regulatory factors in the pericardial cavity may alter cardiac
neurotransmission23 and myocardial
contractility24 25 and may be released by
pericardial or epicardial mesothelial cells.25 26
In view of their position on the outer surface of the heart, some epicardial nerve terminals may be involved also in the detection of inflation of the lungs. Low-pressure inflation was shown to cause a reflex tachycardia27 and is associated with activation of myelinated vagal afferents known to have endings in the lung.28 Electrophysiologically identified receptors in the fibrous layer of canine pericardium also were recently shown to be stimulated by inflation of the lung,29 although concomitant effects on heart rate were not reported. Significantly, the most excitable areas of the pericardium are described as being above the atrial appendages, where we identified a high density of epicardial nerve terminals.
The end net has been regarded traditionally as an atypical mammalian sensory nerve terminal served by myelinated nerves.7 Many workers in this field, however, failed to demonstrate the end net in the endocardium2 ; others confused it with the endocardial plexus itself.11 In the present study, we did not demonstrate any structure arising from myelinated nerves that could be considered to represent a distinct network of nerve fibers.
Specialized Nerve Terminals in the Coronary
Sinus
The presence of nerve terminals within the lumen of, rather than
associated with the mouth of, the coronary sinus appears to be
a finding unique to humans. Physiological
experiments using gross distension of the coronary sinus
demonstrated a lack of nerve terminals in the lumen of experimental
animals, the reflex effects having been attributed to
nonmyelinated afferents in the underlying left atrium
or ventricle.30 31 The significant species variation
observed in this area may be interpreted as an indication of the
increased importance of cardiac venous return inherent in the upright
position of bipeds, the major capacitance fraction being below rather
than above the level of the heart.32
Nonmyelinated Endocardial Nerve
Terminals
Receptors in the atria and left ventricle served
predominantly by vagal and sympathetic nonmyelinated
afferents were identified with
electrophysiological
techniques.5 33 These receptors are believed to be
responsible for many of the most important reflexes in the heart, such
as the reflex vasodilation and bradycardia in response to increasing
venous return or distension of the left ventricle34 and
the vomiting and fainting reflexes.35 They also have a
strong inhibitory effect on sympathetic outflow to the
kidneys,5 influencing not only blood flow but also renin
and antidiuretic hormone release and sodium
secretion.36 37 Evidence is also mounting that, under
certain conditions, a subpopulation of these receptors acts as both
mechanoreceptors and chemoreceptors.38 It is tempting to
speculate that the nerve terminals identified as arising from
nonmyelinated nerves in the endocardial plexus
correspond to those described
electrophysiologically as vagal or
sympathetic sensory C fibers.
Nerve section and denervation studies indicated the sensory nature of cardiac nerve terminals by their origin in the nodose and dorsal root ganglion.39 Contrary to traditional views, however, mammalian primary sensory neurons may express a catecholaminergic phenotype; tyrosine hydroxylase and neuropeptide Y expression was demonstrated in the cell bodies and axons of primary sensory afferents,40 41 including those associated with the carotid sinus baroreceptors and carotid body chemoreceptors.42 In fact, the expression of neuropeptides, such as substance P, which is more often associated with sensory nerves, is low in comparison.41 We found no evidence of calcitonin gene–related peptide or substance P immunoreactivity in either myelinated or nonmyelinated nerve terminals, although both were present in varicose nerve fibers in the endocardial plexus.11
Intrinsic Neurons and Associated Nerve Terminals
Intracardiac
neurons are generally considered to represent
postganglionic parasympathetic neurons receiving input from
parasympathetic preganglionic neurons.43 However, these
neurons also receive input from efferent sympathetic and afferent
neurons, the latter having been
electrophysiologically identified as
cardiac and pulmonary mechanoreceptors.43
Intrinsic cardiac neurons of chronically decentralized canine hearts
also were shown to display a spontaneous activity capable of being
modulated by cardiac mechanoreceptors.44 The present
study gives morphological evidence of a similar local neuronal circuit
in the human heart between intrinsic ganglia and epicardial nerve
terminal arborizations.
Study Limitations
In the endocardium, areas of excessive
trabeculation,
such as parts of the left lateral wall of the right atrium below the
terminal crest and the apical region of the ventricles, do not yield
usable whole mounts and thus, by necessity, were excluded from the
study. In addition, the thickness of the endocardium in the atria
produces a considerable degree of technical difficulty. For the most
effective visualization of nerves and terminals, excess underlying
connective tissue must be removed. Thus, it is possible that deep
subendocardial nerve terminals exist but were not demonstrated;
nonetheless, underlying subendothelial layers were
examined frequently and found to contain only occasional nerve
fascicles. Physiological and
electrophysiological analyses of
human cardiac nerve terminals are desirable, but obtaining these data
presents many difficulties.
|
Acknowledgments |
|---|
This work was supported by grants PG/92053 and PG/940100 from the British Heart Foundation. We thank the staff of the Beaumont Hospital, Dublin, Ireland, and Queens Medical Center, Nottingham, England, and members of the Cardiac Transplant Team, Great Ormond Street Hospital for Children, London, England, for their assistance in the collection of tissue samples and Dr J McComb for reviewing the manuscript.
Received February 6, 1995; revision received April 3, 1995; accepted May 5, 1995.
|
References |
|---|
|
TopAbstractIntroductionMethods Results Discussion References |
|---|
1. Bishop VS, Malliani A, Thoren P. Cardiac mechanoreceptors. In: Berne RM, Sperelakis N, Geiger SR, eds. Handbook of Physiology: The Cardiovascular System. Bethesda, Md: Waverley Press; 1979:497-555.
2. Linden RJ, Kappagoda CT. Histology of sensory nerve endings in the heart. In: Linden RJ, Kappagoda CT, eds. Atrial Receptors. Cambridge, UK: Cambridge University Press; 1982:6-30.
3. Jarish A, Zotterman Y. Depressor reflexes from the heart. Acta Physiol Scand. 1948;16:31-51.
4. Paintal AS. A study of the right and left atrial receptors. J Physiol. 1953;120:596-610.
5.
Thorén P. Atrial receptors with
nonmedullated vagal afferents in the cat. Circ
Res. 1976;38:357-362.
6.
Malliani A, Recordati G, Schwartz PJ.
Nervous activity of afferent cardiac sympathetic fibers with
atrial and ventricular endings. J
Physiol. 1973;229:457-469.
7. Miller MR, Kasahara M. Studies on the nerve endings in the heart. Am J Anat. 1964;115:217-233. [Medline] [Order article via Infotrieve]
8.
Kappagoda CT, Linden RJ, Snow HM. The effect of
stretching the superior vena caval-right atrial junction on right
atrial receptors in the dog. J Physiol. 1972;227:875-887.
9. Hirsch EF, Borghard-Erdle AM. The innervation of the human heart, I: the coronary arteries and the myocardium. Arch Pathol. 1961;71:384-407. [Medline] [Order article via Infotrieve]
10. Williams TH. Mitral and tricuspid valve innervation. Br Heart J. 1964;26:105-115.
11. Marron K, Wharton J, Sheppard MN, Gulbenkian S, Royston D, Yacoub MH, Anderson RH, Polak JM. Human endocardial innervation and its relationship to the endothelium: an immunohistochemical, histochemical and quantitative study. Cardiovasc Res. 1994;28:1490-1499. [Medline] [Order article via Infotrieve]
12. Gulbenkian S, Wharton J, Polak JM. The visualization of cardiovascular innervation in the guinea-pig using antiserum to protein gene product 9.5 (PGP 9.5). J Auton Nerv Syst. 1987;18:235-247. [Medline] [Order article via Infotrieve]
13. Wharton J, Polak JM, Probert L, De Mey J, McGregor GP, Bryant MG, Bloom SR. Peptide containing nerves in the ureter of the guinea-pig and cat. Neuroscience. 1981;6:969-981. [Medline] [Order article via Infotrieve]
14. Kuhn DM, Billingsley MR. Tyrosine hydroxylase: purification from PC-12 cells, characterization, and production of antibodies. Neurochem Int. 1987;11:463-475.
15. Lewis DA, Melchitzky DS, Haycock JW. Four isoforms of tyrosine hydroxylase are expressed in human brain. Neuroscience. 1993;54:477-492. [Medline] [Order article via Infotrieve]
16.
Dey SM, Gu J, Polak JM, Bloom SR. Somatostatin
in the human heart and comparison with guinea pig and rat
heart. Br Heart J. 1985;53:153-157.
17. Wharton J, Gulbenkian S, Mulderry PK, Ghatei MA, McGregor GP, Bloom SR, Polak JM. Capsaicin induces a depletion of calcitonin gene-related peptide (CGRP)-immunoreactive nerves in the cardiovascular system of the guinea pig and rat. J Auton Nerv Syst. 1986;16:289-309. [Medline] [Order article via Infotrieve]
18. Johnson MD, Glick AD, Davis BW. Immunohistochemical evaluation of Leu-7, myelin basic protein, S-100 protein, glial fibrillary acidic protein and Ln3 immunoreactivity in nerve sheath tumors and sarcomas. Arch Pathol Lab Med. 1988;112:155-160. [Medline] [Order article via Infotrieve]
19. Tramu G, Pillez A, Leonardelli J. An efficient method of antibody elution for the successive or simultaneous localisation of two antigens by immunocytochemistry. J Histochem Cytochem. 1978;26:322-324. [Abstract]
20. Arndt JO. Neurophysiological properties of atrial mechanoreceptors. In: Hainsworth R, Kidd C, Linden RJ, eds. Cardiac Receptors. Cambridge, UK: Cambridge University Press; 1979:89-115.
21. Paintal AS. Natural stimulation of type B atrial receptors. J Physiol. 1963;148:240-251.
22. Gupta PD, Henry JP, Sinclair R, Von Baumgarten R. Responses of atrial and aortic baroreceptors to nonhypotensive hemorrhage and to transfusion. Am J Physiol. 1966;211:1429-1437.
23.
Miyazaki T, Pride HP, Zipes DP.
Prostaglandins in the pericardial fluid modulate
neural regulation of cardiac
electrophysiological properties.
Circ Res. 1990;66:163-175.
24.
Appelgate RJ, Little WC. Alteration of autonomic
influence on left ventricular contractility
by epicardial superfusion with hexamethonium and
procaine. Cardiovasc Res. 1994;28:1042-1048.
25. Eid H, de Bold MLK, Chen JH, de Bold AJ. Epicardial mesothelial cells synthesize and release endothelin. J Cardiovasc Pharmacol. 1994;24:715-720. [Medline] [Order article via Infotrieve]
26. Dusting GJ, Nolan RD. Stimulation of prostacyclin release from epicardium of anaesthetized dogs. Br J Pharmacol. 1981;74:553-562. [Medline] [Order article via Infotrieve]
27. Cassidy SS, Eshenbacher WL, Johnson RL. Reflex cardiovascular depression during unilateral lung hyperinflation in the dog. J Clin Invest. 1979;64:620-626.
28.
Kaufman MP, Iwamoto GA, Ashton JH, Cassidy SS.
Responses to inflation of vagal afferents with endings in the
lungs of dogs. Circ Res. 1982;51:525-531.
29.
Kostreva DR, Pontus SP. Pericardial
mechanoreceptors with phrenic afferents. Am J
Physiol. 1993;264:H1836-H1846.
30.
Muers MF, Sleight P. The reflex
cardiovascular depression caused by occlusion of the
coronary sinus in the dog. J
Physiol. 1972;221:259-282.
31.
Muers MF, Sleight P. Action potentials from
ventricular mechanoreceptors stimulated by occlusion of the
coronary sinus in the dog. J
Physiol. 1972;221:283-309.
32. Folkow B. Relevance of cardiovascular reflexes. In: Hainsworth R, Kidd C, Linden RJ, eds. Cardiac Receptors. Cambridge, UK: Cambridge University Press; 1979:473-505.
33.
Sleight P, Widdicombe JG. Action potentials in
fibres from receptors in the epicardium and myocardium of
the dog's left ventricle. J Physiol. 1965;181:235-258.
34.
Salisbury PF, Cross CE, Rieben PA. Reflex effect
of left ventricular distension.
Circ Res. 1960;8:530-534.
35. Abrahamsson H, Thorén P. Vomiting and reflex vagal relaxation of the stomach elicited from heart receptors in the cat. Acta Physiol Scand. 1973;88:433-439. [Medline] [Order article via Infotrieve]
36. Zanchetti A, Stella A, Leonetti G, Morganti A, Teryoli I. Control of renin release: a review of experimental evidence and clinical implications. Am J Cardiol. 1976;37:675-691. [Medline] [Order article via Infotrieve]
37.
Harris MC, Spyer KM. Inhibition of ADH release
by stimulation of afferent cardiac branches of the right vagus in
cats. J Physiol. 1974;237:663-684.
38.
Ustinova EE, Schultz HD. Activation of cardiac
vagal afferents by oxygen-derived free radicals in rats.
Circ Res. 1994;74:895-903.
39. Nettleship WA. Experimental studies on the afferent innervation of the cat's heart. J Comp Neurol. 1936;64:115-133.
40. Katz DM, Adler JE, Black IB. Catecholaminergic primary sensory neurons: autonomic targets and mechanisms of transmitter regulation. Fed Proc. 1987;46:24-29. [Medline] [Order article via Infotrieve]
41. Finley JC, Polak J, Katz DM. Transmitter diversity in carotid body afferent neurons: dopaminergic and peptidergic phenotypes. Neuroscience. 1992;51:973-987. [Medline] [Order article via Infotrieve]
42. Czyzyk-Krzeska MF, Bayliss DA, Lawson EE, Millhorn DE. Expression of messenger RNAs for peptides and tyrosine hydroxylase in primary sensory neurons that innervate arterial baroreceptors and chemoreceptors. Neurosci Lett. 1991;129:98-102. [Medline] [Order article via Infotrieve]
43.
Armour JA, Hopkins DA. Activity of in vivo
canine ventricular neurons. Am J
Physiol. 1990;258:H326-H336.
44.
Ardell JL, Butler CK, Smith FM, Hopkins DA, Armour JA.
Activity of in vivo atrial and ventricular neurons
in chronically decentralized canine hearts. Am J
Physiol. 1991;260:H713-H721.
This article has been cited by other articles:
 |
|
 |
|
  B. Retzlaff, R. Bauernschmitt, H. Malberg, G. Brockmann, C. Uhl, R. Lange, J. Kurths, G. Bretthauer, and N. Wessel Depression of cardiovascular autonomic function is more pronounced after mitral valve surgery: evidence for direct trauma Phil Trans R Soc A, April 13, 2009; 367(1892): 1251 - 1263. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Y. Tan, H. Li, S. Wachsmann-Hogiu, L. S. Chen, P.-S. Chen, and M. C. Fishbein Autonomic Innervation and Segmental Muscular Disconnections at the Human Pulmonary Vein-Atrial Junction: Implications for Catheter Ablation of Atrial-Pulmonary Vein Junction J. Am. Coll. Cardiol., July 4, 2006; 48(1): 132 - 143. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Takahashi, P. Jais, M. Hocini, P. Sanders, M. Rotter, T. Rostock, L.-F. Hsu, F. Sacher, J. Clementy, and M. Haissaguerre Shortening of Fibrillatory Cycle Length in the Pulmonary Vein During Vagal Excitation J. Am. Coll. Cardiol., February 21, 2006; 47(4): 774 - 780. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. Pappone, V. Santinelli, F. Manguso, G. Vicedomini, F. Gugliotta, G. Augello, P. Mazzone, V. Tortoriello, G. Landoni, A. Zangrillo, et al. Pulmonary Vein Denervation Enhances Long-Term Benefit After Circumferential Ablation for Paroxysmal Atrial Fibrillation Circulation, January 27, 2004; 109(3): 327 - 334. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. L. Brutsaert Cardiac Endothelial-Myocardial Signaling: Its Role in Cardiac Growth, Contractile Performance, and Rhythmicity Physiol Rev, January 1, 2003; 83(1): 59 - 115. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P.-S. Chen, L. S Chen, J.-M. Cao, B. Sharifi, H. S Karagueuzian, and M. C Fishbein Sympathetic nerve sprouting, electrical remodeling and the mechanisms of sudden cardiac death Cardiovasc Res, May 1, 2001; 50(2): 409 - 416. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. A. O'Rourke, J. S. Hochman, M. C. Cohen, C. L. Lucore, J. J. Popma, and C. P. Cannon New Approaches to Diagnosis and Management of Unstable Angina and Non-ST-Segment Elevation Myocardial Infarction Arch Intern Med, March 12, 2001; 161(5): 674 - 682. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J.-M. Cao, M. C. Fishbein, J. B. Han, W. W. Lai, A. C. Lai, T.-J. Wu, L. Czer, P. L. Wolf, T. A. Denton, I. P. Shintaku, et al. Relationship Between Regional Cardiac Hyperinnervation and Ventricular Arrhythmia Circulation, April 25, 2000; 101(16): 1960 - 1969. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J.-M. Cao, L. S. Chen, B. H. KenKnight, T. Ohara, M.-H. Lee, J. Tsai, W. W. Lai, H. S. Karagueuzian, P. L. Wolf, M. C. Fishbein, et al. Nerve Sprouting and Sudden Cardiac Death Circ. Res., April 14, 2000; 86(7): 816 - 821. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Duru, U. Bauersfeld, and R. Candinas Autonomic effects of radiofrequency catheter ablation Europace, January 1, 2000; 2(2): 181 - 185. [Abstract] [PDF]
|
|
|
|
|
|
M.-H. Hsieh, C.-W. Chiou, Z.-C. Wen, C.-H. Wu, C.-T. Tai, C.-F. Tsai, Y.-A. Ding, M.-S. Chang, and S.-A. Chen Alterations of Heart Rate Variability After Radiofrequency Catheter Ablation of Focal Atrial Fibrillation Originating From Pulmonary Veins Circulation, November 30, 1999; 100(22): 2237 - 2243. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Singh, P. I. Johnson, A. Javed, T. S. Gray, V. A. Lonchyna, and R. D. Wurster Monoamine- and Histamine-Synthesizing Enzymes and Neurotransmitters Within Neurons of Adult Human Cardiac Ganglia Circulation, January 26, 1999; 99(3): 411 - 419. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. L. Brutsaert, P. Fransen, L. J. Andries, G. W. De Keulenaer, and S. U. Sys Cardiac endothelium and myocardial function Cardiovasc Res, May 1, 1998; 38(2): 281 - 290. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Marron, M. H. Yacoub, J. M. Polak, M. N. Sheppard, D. Fagan, B. F. Whitehead, M. R. de Leval, R. H. Anderson, and J. Wharton Innervation of Human Atrioventricular and Arterial Valves Circulation, August 1, 1996; 94(3): 368 - 375. [Abstract] [Full Text]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||