Nitric oxide synthase in the brain of the turtle Pseudemys scripta elegans

Abstract

The distribution pattern of nitric oxide synthase (NOS) was investigated in the brain of the turtle by NADPH-diaphorase histochemistry. The specificity of the histochemical staining was tested by immunocytochemical colocalization with an antiserum specific for NOS. In the forebrain, neurons staining intensely for nitric oxide synthase were localized in the olfactory tubercle, the basal ganglia complex, the basal amygdaloid nucleus, suprapeduncular nucleus, and the posterior hypothalamic area. Many positive fibers course in a tract connecting the basal amygdaloid nucleus with the hypothalamus, corresponding to the stria terminalis. Bundles of nitroxergic fibers were seen to course at the ventromedial edge of the optic tract and to cross in the supraoptic decussation, apparently consisting of tectothalamic and thalamotectal fibers. In the midbrain, strongly NOS-positive neurons were present in the substantia nigra, the nucleus profundus mesencephali, the periventricular grey of the optic tectum, the laminar nucleus of the torus semicircularis, and the nucleus of the lateral lemniscus. The area of the locus coeruleus harbored an accumulation of intensely stained neurons, which, as in mammals, might represent a cholinergic cell group of the reptilian brainstem. In the cerebellum, strong staining was confined to bundles of afferent fibers running in the lower molecular and in the Purkinje cell layer. These axons appeared to include ascending projections from the dorsal funicular nucleus or the spinal cord. NOS-positive cells in the caudal brainstem were found in the cerebellar nuclei, in the superior vestibular nucleus, in the reticular nuclei, ventrolateral to the nucleus of the solitary tract, in the perihypoglossal, and in the dorsal funicular nucleus. Taken together, these results suggest that nitric oxide acts as a messenger molecule in different areas of the reptilian brain and spinal cord. In certain areas, the pattern of expression of NOS appears to have evolved before radiation of present mammalian, avian, and reptilian species.

Nitric oxide synthase and background adaptation in Xenopus laevis

“…The distribution of NADPH-d + neurons corroborates the findings of Brü ning and Mayer (1996) in Xenopus lae6is and is also in line with recent studies in other amphibian species Muñ oz et al, 1996) and in some reptiles (Brü ning et al, 1994;Smeets et al, 1997) (reviewed in Allaerts et al, 1997). In the rat, it was shown that NOS catalytic activity is responsible for NADPH-d staining (Hope et al, 1991;Dawson et al, 1991), although some tissues like the adrenal cortex and the liver display NADPH-d activity in the absence of NOS (Dawson et al, 1991).…”

“…Recently, the neuroanatomical distribution of NOSimmunoreactive neurons and the distribution of inicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) positive neurons has been described in a number of amphibian (Brü ning and Mayer, 1996;Muñ oz et al, 1996;González et al, 1996) and reptilian species (Brü ning et al, 1994;Smeets et al, 1997). Muñ oz et al (1996) suggest that the function of NO in the amphibian brain, considered to be primarily related to forebrain activities, may have been well preserved during vertebrate evolution (Allaerts et al, 1997).…”

Distribution of NADPH-Diaphorase-Positive Neurons in the Mouse Brain: Differences from Previous Findings in the Rat Brain and Comparison with the Distribution of Serotonergic Neurons.

“…Many large NADPH-d-positive neurons were histochemically detected in the globus pallidus of the turtle, extending into the lateral forebrain bundle. Many fibers originating in the region between the dorsal and ventral portions of the lateral forebrain bundle passed through the globus pallidus [3]. In the globus pallidus, very lightly NADPH-d staining fibers and cell bodies were observed in our study, so it is difficult to conclude whether the projections were efferent or afferent.…”

Nitric oxide synthase-dependent NADPH-diaphorase activity in the optic lobes of male and female Ceratitis capitata mutants

“…Moreover, NO could influence behavioural differences linked to vision in the two sexes. T he gas nitric oxide (NO) is recognized as an important signalling molecule in the nervous system (Moncada et al, 1991;Bredt & Snyder, 1990), not only in mammals (Bredt & Snyder, 1990;Garthwaite, 1991;Garthwaite et al, 1988;Snyder, 1992;Vincent & Kimura, 1992), but also in all the vertebrate groups (Williams et al, 1994;Brüning et al, 1994;Holqvist et al, 1994;Pisu et al, 2002) and in several invertebrates (Martinez, 1995;Müller & Bicker, 1994;Kurzin et al, 1996;Gibbs & Truman, 1996;Elphick et al, 1996;Pisu et al, 1999).…”