title: Organization of the nitrergic neuronal system in the primitive bony fishes Polypterus senegalus and Erpetoichthys calabaricus (Actinopterygii: Cladistia).
abstract: Cladistians are a group of basal actinopterygian fishes that constitute a good model for studying primitive brain features, most likely present in the ancestral bony fishes. The analysis of the nitrergic neurons (with the enzyme nitric oxide synthase; NOS) has helped in understanding important aspects of brain organization in all vertebrates studied. We investigated the nitrergic system of two cladistian species by means of specific antibodies against NOS and NADPH-diaphorase (NADPH-d) histochemistry, which, with the exception of the primary olfactory and terminal nerve fibers, labeled only for NADPH-d, yielded identical results. Double immunohistochemistry was conducted for simultaneous detection of NOS with tyrosine hydroxylase, choline acetyltransferase, calbindin, calretinin, and serotonin, to establish accurately the localization of the nitrergic neurons and fibers and to assess possible interactions between these neuroactive substances. The pattern of distribution in both species showed only subtle differences in the density of labeled cells. Distinct groups of NOS-immunoreactive cells were observed in pallial and subpallial areas, paraventricular region, tuberal and retromammillary hypothalamic areas, posterior tubercle, prethalamic and thalamic areas, optic tectum, torus semicircularis, mesencephalic tegmentum, interpeduncular nucleus, superior and middle reticular nuclei, magnocellular vestibular nucleus, solitary tract nucleus, nucleus medianus magnocellularis, the spinal cord and amacrine cells in the retina. Large neurons in cranial nerve sensory ganglia were also labeled. The comparison of these results with those from other vertebrates, using a neuromeric analysis, reveals a conserved pattern of organization of the nitrergic system from this primitive fish group to amniotes, including mammals.
authors.affiliation: Department of Cell Biology, Faculty of Biology, University Complutense, 28040, Madrid, Spain.
authors.forename: Jesús M
authors.initials: JM
authors.lastname: López
authors.affiliation: Department of Cell Biology, Faculty of Biology, University Complutense, 28040, Madrid, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Lozano
authors.affiliation: Department of Cell Biology, Faculty of Biology, University Complutense, 28040, Madrid, Spain.
authors.forename: Ruth
authors.initials: R
authors.lastname: Morona
authors.affiliation: Department of Cell Biology, Faculty of Biology, University Complutense, 28040, Madrid, Spain.
authors.forename: Agustín
authors.initials: A
authors.lastname: González
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology*; D001931:Brain Mapping; D064032:Calbindin 2 / Q000378:metabolism; D064026:Calbindins / Q000378:metabolism; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D005399:Fishes / Q000033:anatomy & histology*; D009252:NADPH Dehydrogenase / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D064032:Calbindin 2; D064026:Calbindins; D009419:Nerve Tissue Proteins; D012701:Serotonin; D019001:Nitric Oxide Synthase; D014446:Tyrosine 3-Monooxygenase; D009252:NADPH Dehydrogenase; D002795:Choline O-Acetyltransferase
keywords: AB_10000321; AB_10000347; AB_2079751; AB_2314957; AB_572263; AB_572268; NADPH diaphorase; Polypteridae; bichir; brain evolution; immunohistochemistry; nitric oxide synthase