title: Postganglionic nerve cell bodies and neurotransmitter localization in the teleost heart.
abstract: A study was undertaken to determine the distribution of specific types of autonomic nerves and the presence of various transmitter substances in the heart of two teleost species: the mullet (Mugil cephalus) and the Nile catfish (Synodontis nigriventris). Large nerve trunks in the sinus venosus were shown to contain tyrosine hydroxylase immunoreactivity and indicate the location of adrenergic nerve fibers, which are also associated with a coronary circulation to the ventricular myocardium in the mullet heart. Fluorescence immunolabelling methods revealed that the atrium and the outer and inner compact muscle of the ventricle have nerves in which substance P and galanin (GA) are localized. It seems likely that the cell bodies (perikarya) of the substance P and GA-immunopositive axons are located at sites outside the heart. The GA-immunopositive nerve fibers may represent a population of axons of intramural postganglionic nerve cell bodies. Most intracardiac nerve cell bodies are located in the sinus venosus and in the sinoatrial junction and reveal immunoreactivity to substance P, GA, neuronal nitric oxide synthase (nNOS), vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating peptide (PACAP). Furthermore, substance P immunoreactivity is present in the cardiac cells intermingled with the substance P-immunopositive nerve fibers. A nerve plexus consisting of a well-developed network of nerve fibers and nerve cell bodies may possibly correspond to a cardiac pacemaker, but its function in fish cardiac regulation is unknown and remains to be elucidated.
authors.affiliation: Department of Animal Biology and Marine Ecology, Faculty of Science, Section of Comparative Neurobiology and Biomonitoring, University of Messina, I-98166 Messina, Italy. gzaccone@unime.it
authors.forename: Giacomo
authors.initials: G
authors.lastname: Zaccone
authors.forename: Angela
authors.initials: A
authors.lastname: Mauceri
authors.forename: Maria
authors.initials: M
authors.lastname: Maisano
authors.forename: Alessia
authors.initials: A
authors.lastname: Giannetto
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Parrino
authors.forename: Salvatore
authors.initials: S
authors.lastname: Fasulo
mesh_terms: D000818:Animals; D005399:Fishes; D006321:Heart / Q000294:innervation*; D008856:Microscopy, Fluorescence; D009206:Myocardium / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism
chemical_list: D018377:Neurotransmitter Agents; D052248:Nitric Oxide Synthase Type I