Histochemical and immunocytochemical localization of nitric oxide synthase in the central nervous system of the goldfish, Carassius auratus

Abstract

The distribution of the neuronal type of nitric oxide synthase in the goldfish brain and spinal cord was investigated via NADPH-diaphorase histochemistry and immunocytochemistry using an antiserum raised against the purified mammalian enzyme. Many structures, including magnocellular neurosecretory cells, motoneurons, mesencephalic trigeminal neurons, and radial glial fibers, were stained by the NADPH-diaphorase reaction but were not immunoreactive. This nonspecific NADPH-diaphorase activity was strongly reduced after preincubation of the sections. Therefore, when sections were first reacted for immunofluorescence and, thereafter, stained for NADPH-diaphorase, a corresponding staining pattern was obtained that allowed the reliable localization of neuronal nitric oxide synthase based on both complementary staining methods. In the telencephalon, positive neurons were concentrated in the ventral and posterior parts of the area ventralis. Many intensely stained neurons were present in various diencephalic nuclei, including the nucleus centralis posterior and the ventromedial nucleus of the thalamus, the nucleus tori lateralis, the nucleus recessus lateralis, the nucleus tuberis posterior, and the central nucleus of the inferior lobe. In the midbrain, neurons containing nitric oxide synthase were located in the periventricular zone of the optic tectum, the nucleus vermiformis, and the nucleus reticularis mesencephali. Specific staining in the cerebellum was concentrated in Golgi cells. In the hindbrain, nitroxergic neurons were numerous in all four sensory nuclei of the trigeminus, in the facial lobe, the superior olive, the inferior reticular formation, and the medial general visceral nucleus of the vagus. The dorsal horn of the spinal cord was enriched with positive neurons. A few strongly stained cells were also present in the ventral horn. In conclusion, neurons capable of synthesizing nitric oxide occur throughout the teleost central nervous system. The presence of nitric oxide synthase in projection areas of most afferent nerves suggests a widespread involvement of nitric oxide in sensory information processing. The distribution of nitric oxide synthase-containing neurons in certain areas, e.g., the tectum opticum and the spinal cord, indicates an evolutionarily conserved pattern. Similar to the case in other vertebrates, there appears to be no comprehensive overlap between the distribution of nitric oxide synthase and that of any other chemically characterized neuronal population described thus far. However, strongly positive cell groups in the mesencephalic reticular formation suggest the idea of an evolutionarily conserved mesopontine cholinergic system coexpressing nitric oxide synthase.

Participation of Neurochemical Signaling in Adult Neurogenesis and Differentiation

“…The presence of such fibers and CBS-ip endings in interganglionic plexus of corpus cerebelli, possibly reflecting the sinaptical method of release of H 2 S in this area of the masu salmon brain. The presence of NOergic cells and fibers was shown in the cerebellum on different species of fish by histochemical marking of NADPH-d [4,44,45]. Detection of nNOS in eurydendroid cells of masu salmon cerebellum confirms received our earlier data on histological labelling of NADPH-d in the neurons of this type of fish [46].…”

Nitric oxide metabolites in goldfish under normoxic and hypoxic conditions

“…In fish, significant NOS expression has been reported in brain, heart and gills (Brüning et al, 1995;Holmqvist et al, 2000;Tota et al, 2005;Ebbesson et al, 2005;Hyndman et al, 2006), the tissues with the highest nitrite levels in goldfish. The values of [SNO] and [FeNO + NNO] in tissues range from practically zero (below detection level) in the gills (Fig.8C) to values that are comparable with nitrite concentrations in kidney and liver (Fig.7), which points to significant differences in the extent and importance of nitros(yl)ation reactions among tissues.…”

Development of NADPH-Diaphorase Activity in the Central Nervous System of the Cichlid Fish, Tilapia mariae

“…Nitric oxide plays an essential role in the normal functioning of the nervous system, and furthermore, NO could be involved in synaptic plasticity [Hölscher, 1997], in longterm potentiation [Bohme et al, 1991] and in the development of neuronal connectivities [Gally et al, 1990;Williams et al, 1994]. The distribution of NADPH-diaphorase-positive neurons have been extensively studied in teleosts [Schober et al, 1993;Holmqvist et al, 1994;Villani et al, 1994;Arévalo et al, 1995;Brüning et al, 1995;Villani andGuarnieri, 1995a, b, 1996;Anken and Rahman, 1996;Anken et al, 1996a] and in the larval lamprey [Schober et al, 1994a;Zielinski et al, 1996]. The results indicate the early appearance of NO in vertebrate evolution and suggest its involvement in motor and sensory function [Gibbins et al, 1995;Turner and Moroz, 1995;Anken et al, 1996b].…”