title: Identifiable nitrergic neurons in the central nervous system of the nudibranch Melibe leonina localized with NADPH-diaphorase histochemistry and nitric oxide synthase immunoreactivity.
abstract: Nitric oxide (NO) is a gaseous intercellular messenger produced by the enzyme nitric oxide synthase (NOS). In this study, we used two different techniques-nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry and NOS immunocytochemistry-to demonstrate that NOS is present in a pair of identifiable cells in the central nervous system of the nudibranch Melibe leonina. In the Melibe brain, NADPH-d histochemistry revealed only a single pair of bilaterally symmetrical cells in the cerebropleural ganglia. NOS activity also was found in the neuropil of the cerebral, pedal, and buccal ganglia; in the tentacles of the oral hood; in the sensory end of the rhinophores; and in the epithelial tissue of the mouth, preputium, and glans penis. Immunocytochemistry using NOS antisera corroborated the results of the NADPH-d histochemistry by staining the same two cells in the cerebropleural ganglia. Each of these identifiable nitrergic neurons projects into the ipsilateral pedal ganglion. Because the pedal ganglia play a critical role in the control of locomotion, our results provide morphological evidence suggesting that NO may influence swimming or crawling in Melibe leonina.
authors.affiliation: Zoology Department and Center for Marine Biology, University of New Hampshire, Durham, NH 03824, USA. bnewcomb@juno.com
authors.forename: J M
authors.initials: JM
authors.lastname: Newcomb
authors.forename: W H
authors.initials: WH
authors.lastname: Watson
mesh_terms: D000818:Animals; D000906:Antibodies; D017952:Ganglia, Invertebrate / Q000166:cytology / Q000201:enzymology; D007150:Immunohistochemistry; D008974:Mollusca / Q000378:metabolism*; D009252:NADPH Dehydrogenase / Q000032:analysis* / Q000276:immunology; D009420:Nervous System / Q000166:cytology / Q000201:enzymology; D009474:Neurons / Q000201:enzymology*; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000032:analysis* / Q000276:immunology
chemical_list: D000906:Antibodies; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D009252:NADPH Dehydrogenase