Distribution of vasoactive intestinal polypeptide-like immunoreactivity in the mammalian heart. Interrelation with neurotensin- and substance P-like immunoreactive nerves.
The distribution of vasoactive intestinal polypeptide (VIP) immunoreactivity has been studied in the mammalian heart and compared with that of neurotensin and substance P by use of light-microscopic peroxidase-antiperoxidase immunohistochemistry. VIP-immunoreactive cell bodies are present in intracardiac ganglia in various locations. VIP-immunoreactive nerve fibers predominate in the atria and the conduction system but are rare in the ventricles and occur in cardiac ganglia, endocardium, and epicardium. VIP-ergic nerves supply the coronary vasculature having a preference for the microvasculature and the nodal cells of the sinuatrial node. The large vessels of the heart and periarterial cardiac glomera also receive a VIP-immunoreactive nerve supply. There is partial co-distribution with neurotensin- and substance P-immunoreactive nerve fibers but no co-location in identical nerve fibers is detectable. The VIP-ergic cardiac innervation, which is probably predominantly intrinsic, may stem from postganglionic parasympathetic neurons and is less substantial than the more homogeneous neurotensin-ergic and substance P-ergic nervous supply which is probably extrinsic. The occurrence of an extrinsic VIP-ergic cardiac innervation cannot be excluded however. The differential histotopography of the multitarget cardiac nerves containing the cardiovascular active peptides VIP, neurotensin and substance P may suggest multiple and complex peptide-peptide and peptide-classical transmitter interactions. These may contribute to the regulation of various cardiac functions.
D000818:Animals; D004285:Dogs; D005260:Female; D006168:Guinea Pigs; D006321:Heart / Q000294:innervation*; D007124:Immunoenzyme Techniques; D008297:Male; D009206:Myocardium / Q000032:analysis; D009412:Nerve Fibers / Q000032:analysis*; D009496:Neurotensin / Q000032:analysis*; D051381:Rats; D013045:Species Specificity; D013373:Substance P / Q000032:analysis; D014417:Tupaia; D014660:Vasoactive Intestinal Peptide / Q000032:analysis*
D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D009496:Neurotensin