Co-localization of neuronal nitric oxide synthase with arginine–vasotocin in the preoptic–hypothalamo–hypophyseal system of the teleost Oreochromis niloticus

Abstract

This study provides evidence that, in the preoptic–hypothalamo–hypophysial system of the teleost Oreochromis niloticus, several sub-populations of arginine–vasotocin (AVT)-producing neurons and neurosecretory fibers terminals express neuronal nitric oxide synthase (nNOS)-like molecules. The co-localization between nNOS and AVT was demonstrated by means of double immunofluorescence staining with the confocal microscope. This study is the first to provide evidence that nNOS may be co-localized with AVT in neurons of a non-mammalian vertebrate.