Expression of Nitric Oxide Synthase in the Preoptic-Hypothalamo-Hypophyseal System of the Teleost <i>Oreochromis niloticus</i>

Abstract

In the present study, we have analyzed the expression of nitric oxide synthase (NOS) in the preoptic-hypothalamo-hypophyseal system of the teleost Oreochromis niloticus. The assay for enzyme activity demonstrated that a constitutive NOS activity is present both in soluble and particulate fractions of the homogenates of diencephalons. Western blot analysis using an antibody against the N-terminus of human nNOS revealed two bands both in the supernatant and in the pellet. One band co-migrates at approximately 150 kDa with that detected in the rat cerebellum homogenates and presumably corresponds to neuronal NOS (nNOS) of mammals. The additional band, which migrates at approximately 180 kDa, might be attributed to an alternatively spliced nNOS isoform. Using NADPH diaphorase (NADPHd) histochemistry in combination with NOS immunohistochemistry, nNOS expression has been detected in preoptic nuclei, hypophysiotrophic nuclei of the ventral hypothalamus, and the pituitary gland. Various degrees of dissociation of NADPHd activity and nNOS immunoreactivity have been detected that could be attributed to the expression of different subtypes of nNOS in the preoptic/hypothalamo/hypophysial system of tilapia. In this paper, we also investigated the colocalization of nNOS with arginine-vasotocin (AVT) by means of immunolabeling of consecutive sections. Results suggest that NO may be colocalized with AVT in a subpopulation of neurosecretory neurons. Present findings suggest that nitric oxide (NO) is implicated in the modulation of hormone release in teleosts in a similar way to mammals.

Nitric Oxide Synthase and NADPH Diaphorase Distribution in the Bullfrog <i>(Rana catesbeiana)</i> CNS: Pathways and Functional Implications

“…Both vasopressin and oxytocin have been co-localized with NOS in rats [Nylen et al, 2001a, b;Xiao et al, 2005]. Likewise in a teleost fish, neuronal NOS is co-localized with vasotocin [Bordieri et al, 2003;Bordieri and Cioni, 2004]. On the other hand, vasotocin is not co-localized with NADPHd staining in two bird species [Sanchez et al, 1996].…”

“…For example, NOS is present in the most primitive of metazoans, the sponges, as well as mollusks, annelids, cnidarians and arthropods [Leake and Moroz, 1996;Moroz and Gillette, 1996;Korneev et al, 1998;Giovine et al, 2001;Kitamura et al, 2001;Rast, 2001;Watson et al, 2001;Bullerjahn and Pfluger, 2003;Christie et al, 2003;Moroz et al, 2004;Kurylas et al, 2005]. NOS-immunoreactivity (NOS-ir) in non-mammalian vertebrate brains has been detected in various fishes [Brüning et al, 1995;Villani et al, 2001;Bordieri et al, 2003;Singru et al, 2003;Ando et al, 2004;Masini et al, 2005], reptiles [Brüning et al, 1994b;Smeets et al, 1997;Haverkamp et al, 2000], and birds [Brüning et al, 1994a;Garcia-Calero et al, 2002;Balthazart et al, 2003]. Amphibians are particularly important in this regard, as they provide excellent model systems for behavioral studies [Deban et al, 2001;Arbib, 2003;Woolley et al, 2004;Moore et al, 2005;Wilczynski et al, 2005].…”

Pattern of Nitrergic Neuronal System Organization in the Brain of Two Holostean Fishes (Actinopterygii: Ginglymodi)

“…References: agnathans: Schober et al, 1994a;Kyriakatos et al, 2009;chondrichthyes: Shiells and Falk, 1992;Pérez et al, 1995;Álvarez-Otero et al, 1996;Funakoshi et al, 1997;Ferrando et al, 2012;Pose-Mendez et al, 2014;cladistians: López et al, 2016;chondrosteans: Pushchina and Obukhov, 2012;teleosts: Holmqvist et al, 1994teleosts: Holmqvist et al, , 2000Ostholm et al, 1994;Arévalo et al, 1995;Brüning et al, 1995;Anken and Rahmann, 1996;Cioni et al, 1997;Pottek et al, 1997;Funakoshi et al, 1999;Baby et al, 2000;Oyan et al, 2000;Haamedi and Djamgoz, 2002;Bordieri et al, 2003Bordieri et al, , 2005Singru et al, 2003;Ando et al, 2004;Bordieri and Cioni, 2004;Pushchina and Diuĭzen, 2004;Pushchina, 2007;Pushchina et al, 2007;Giráldez-Pérez et al, 2008Gaikwad et al, 2009;Pushchina and Obukhov, 2010;Ganz et al, 2012;lungfishes: Schober et al, 1994b;Northcutt, 2009;amphibians: Nöll et al, 1994;Crowe et al, 1995;Kurenni et al, 1995;Brüning and Mayer, 1996;González et al, 1996González et al, , 2002b…”

Undifferentiated Catecholaminergic and NO-Producing Cells of Forebrain Matrix Zones and Intercellular Relationships in Periventricular Diencephalon of Juvenile Oncorhynchus masou

“…Hypophysotropic nuclei of diencephalon in teleost´s brain contain periventricular nitroxidergic neurons [1][2][3]. The presence of NO-synthesizing cell groups in the periventricular diencephalic nuclei, despite for interspecies differences in teleosts is the most consistent [4][5][6][7].…”