INABIS '98 - Nitric Oxide Synthase (NOS) In The Neuroendocrine Systems Of Teleost Fishes

Nitric Oxide Synthase (NOS) In The Neuroendocrine Systems Of Teleost Fishes
Cioni, C (Dept. of Animal and Human Biology, La Sapienza University, Rome, Italy)
Bordieri, L. (Dept. of Animal and Human Biology, La Sapienza University, Rome, Italy)
De Vito, L. (Dept. of Animal and Human Biology, La Sapienza University, Rome, Italy)
Francia, N. (Dept. of Animal and Human Biology, La Sapienza University, Rome, Italy)
Greco, A. (Dept. of Animal and Human Biology, La Sapienza University, Rome, Italy)
Colasanti, M (Dept. of Biology, Third University of Rome, Italy)
Venturini, G (Dept. of Biology, Third University of Rome, Italy)

Contact Person: Carla Cioni (Cioni@axrma.uniroma1.it)

Abstract

Aim of the study was to investigate the possible involvement of nitric oxide (NO) in fish neuroendocrine systems. The presence of NOS (nitric oxide synthase)-like molecules was demonstrated by means of NADPH-diaphorase staining and NOS immunohistochemistry, in both the cranial and the caudal neurosecretory system (CNSS) of the teleost Oreochromis niloticus (italic). The ultrastructural localization of neuronal NOS was studied in the CNSS by means of immunogold electron microscopy. The presence and the activity of NOS, and NO production in the caudal spinal cord were evaluated by means of the Western blotting method, NOS activity assay, and spectroscopic analysis. Results demonstrated that a NADPH/Ca2+ -dependent NOS activity is present in the soluble and in the particulate fractions of fish spinal cord homogenates, both activities being inhibited by calmodulin inhibitors and by the NOS antibodies showed that the soluble enzyme corresponds to the brain NOS (NOS-I) of mammals, whereas the particulate one is likely attributable to NOS I and/or NOS III (ecNOS) enzymes. To confirm the NO production by the caudal spinal cord homogenates, the NO-mediated conversion of oxyhemoglobin to methemoglobin was monitored spectroscopically. The present results suggest that NO participate in the fish neuroendocrine regulation.

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Poster Number PAcioni0656
Keywords: nitric oxide (NO), NOS, neuroendocrine, teleost fishes, CNSS

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Cioni, C; Bordieri, L.; De Vito, L.; Francia, N.; Greco, A.; Colasanti, M; Venturini, G; (1998). Nitric Oxide Synthase (NOS) In The Neuroendocrine Systems Of Teleost Fishes. Presented at INABIS '98 - 5th Internet World Congress on Biomedical Sciences at McMaster University, Canada, Dec 7-16th. Available at URL http://www.mcmaster.ca/inabis98/pharmtox/cioni0656/index.html