Innervation and neurotransmitter localization in the lung of the Nile bichir Polypterus bichir bichir.
Anatomical and functional studies of the autonomic innervation in the lung of dipnoan fishes and the bichirs are lacking. The present immunohistochemical studies demonstrated the presence of nerve fibers in the muscle layers of the lung of the bichir, Polypterus bichir bichir, and identified the immunoreactive elements of this innervation. Tyrosine hydroxylase, acetylcholinesterase, and peptide immunoreactivity was detected in the intramural nerve fibers. Extensive innervation was present in the submucosa where adenylatecyclase/activating polypeptide 38, substance P, P(2)X(2), and 5-hydroxytryptamine (5-HT)-immunoreactive nerve fibers mainly supplied blood vessels. A collection of monopolar neurons located in the submucosal and the muscular layers of the glottis expressed a variety of various transmitters. These neurons may be homologous to ganglion cells in the branchial and pharyngeal rami of the vagus in fishes. Nerves containing 5-HT and P(2)X(2) receptor immunoreactivity projected to the lung epithelium. Associated with neuroepithelial cells in mucociliated epithelium, were neuronal nitric oxide synthase-immunopositive axons. The physiological function of this innervation is not known. The present study shows that the pattern of autonomic innervation of the bichir lung may by similar in its elements to that in tetrapods.
Zaccone
Giacomo
G
University of Messina, Department of Animal Biology and Marine Ecology, Faculty of Science, Section of Comparative Neurobiology and Biomonitoring, Messina, Italy. gzaccone@unime.it
Mauceri
Angela
A
Maisano
Maria
M
Giannetto
Alessia
A
Parrino
Vincenzo
V
Fasulo
Salvatore
S
D000110:Acetylcholinesterase / Q000032:analysis; D000818:Animals; D017776:Autonomic Pathways / Q000737:chemistry* / Q000201:enzymology; D029941:Fish Proteins / Q000032:analysis*; D005399:Fishes / Q000033:anatomy & histology*; D005455:Fluorescent Antibody Technique; D008168:Lung / Q000294:innervation*; D018377:Neurotransmitter Agents / Q000032:analysis*; D052248:Nitric Oxide Synthase Type I / Q000032:analysis; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000032:analysis; D018048:Receptors, Purinergic P2 / Q000032:analysis; D058476:Receptors, Purinergic P2X2; D044406:Receptors, Serotonin, 5-HT3 / Q000032:analysis; D020545:Respiratory Mucosa / Q000294:innervation; D009418:S100 Proteins / Q000032:analysis; D012701:Serotonin / Q000032:analysis; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis; D014660:Vasoactive Intestinal Peptide / Q000032:analysis
D029941:Fish Proteins; D018377:Neurotransmitter Agents; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D018048:Receptors, Purinergic P2; D058476:Receptors, Purinergic P2X2; D044406:Receptors, Serotonin, 5-HT3; D009418:S100 Proteins; D012701:Serotonin; D014660:Vasoactive Intestinal Peptide; D052248:Nitric Oxide Synthase Type I; D014446:Tyrosine 3-Monooxygenase; D000110:Acetylcholinesterase