Gonadotropin-releasing hormone-immunoreactive neurons and associated nicotinamide adenine dinucleotide phosphate-diaphorase-positive neurons in the brain of a teleost, Rhodeus amarus.

Using combined nicotinamide adenine dinucleotide phosphate-diaphorase (NADPHd) histochemistry and salmon gonadotropin-releasing hormone (sGnRH) immunocytochemistry, it is reported for the first time that possible potential contacts occur between the nitric oxide (NO)- and the GnRH-containing neurons in the brain of a freshwater teleost, Rhodeus amarus. GnRH-immunoreactive (ir) neurons were observed in the olfactory nerve (OLN), olfactory bulb (OB), medial olfactory tract (MOT), ventral telencephalon (VT), nucleus preopticus periventricularis (NPP), nucleus lateralis tuberis (NLT), and midbrain tegmentum (MT). Although NADPHd neurons were widely distributed in the brain, only those having an association with GnRH-ir neurons are described.

Distribution of NADPH-diaphorase activity in the hypothalamo-hypophysial system of the frog, Rana esculenta.

Using nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase (ND) histochemistry, this study reports a wide distribution of ND activity in the hypothalamus, and for the first time in the median eminence (ME), the neural lobe (NL) and in the pars distalis (PD) of the frog, Rana esculenta. Perikarya are ND-active within the nucleus preopticus (NPO), the nucleus preopticus periventricularis (NPP), located around the preoptic recess (PR), the suprachiasmatic nucleus (SCN) and within five infundibular nuclei. Several ND-positive neurons of the nucleus infundibularis ventralis are cerebrospinal fluid-contacting in nature, while a few occupy a subependymal region.

Immunocytochemical localization of taurine in the pineal organ and retina of an anadromous fish, Plecoglossus altivelis.

Light and electron microscopic immunolocalization of taurine, a sulfur-containing free amino acid, was investigated in the photoneuroendocrine pineal organ and the retinal photoreceptor and pigment epithelial layer of the ayu Plecoglossus altivelis, an anadromous fish. Intense immunostaining was found in the outer segments of pineal photoreceptors and retinal cone-like cells. Moderate but definite immunostaining was found in the cytoplasmic processes of pineal supporting cells, the outer segments of retinal rod-like cells, and the apical processes of pigment epithelial cells.

Immunocytochemical demonstration of taurine in the retina and pineal organ of the pigeon.

Taurine-like immunoreactivity (TLI) is found in the pigeon retina at high levels within cones, in select cells of the inner nuclear layer and in sublaminae of the inner plexiform layer. At the ultrastructural level a high density of immuno-gold particles in visualized in the ellipsoid, but not in the paraboloid area of the inner segment. It is present in perikarya and the presynaptic endings of cones, but not in postsynaptic cell processes.