TOPOGRAPHICAL RELATIONSHIP BETWEEN NEURONAL NITRIC-OXIDE SYNTHASE IMMUNOREACTIVITY AND CYCLIC 3',5'-GUANOSINE MONOPHOSPHATE ACCUMULATION INTHE BRAIN OF THE ADULT XENOPUS-LAEVIS

Citation
W. Allaerts et al., TOPOGRAPHICAL RELATIONSHIP BETWEEN NEURONAL NITRIC-OXIDE SYNTHASE IMMUNOREACTIVITY AND CYCLIC 3',5'-GUANOSINE MONOPHOSPHATE ACCUMULATION INTHE BRAIN OF THE ADULT XENOPUS-LAEVIS, Journal of chemical neuroanatomy, 15(1), 1998, pp. 41-56
Citations number
56
Categorie Soggetti
Biology,Neurosciences
ISSN journal
08910618
Volume
15
Issue
1
Year of publication
1998
Pages
41 - 56
Database
ISI
SICI code
0891-0618(1998)15:1<41:TRBNNS>2.0.ZU;2-F
Abstract
Previous immunohistochemical staining procedures of the brain and pitu itary in Xenopus laevis, using an antiserum against neuronal nitric ox ide (NO) synthase (nNOS) and nicotinamide adenine dinucleotide phospha te-diaphorase histochemistry, have revealed NOS activity in neurons an d fibers in a number of brain areas, as well as in fibers in the pitui tary. In the present study we have localized the target structures of the NOergic system in the Xenopus brain by visualizing the sites of NO -sensitive cyclic 3',5'-guanosine monophosphate (cGMP) accumulation, a ccording to a method for cGMP visualization in rat brain slices. Brain slices of unfixed Xenopus are incubated in the presence of the phosph odiesterase inhibitor isobutylmethylxanthine and the NO donor sodium n itroprusside, followed by fixation and cryosectioning. Sections were t hen processed for immunohistochemistry using rabbit and sheep antisera against cGMP and a sheep antiserum against nNOS. Visualization of sin gle and double labeling of cGMP immunoreactive and/or nNOS immunoreact ive structures was performed with combined CY3/fluorescein isothiocyan ate fluorescence microscopy. Following this procedure, we provide immu nohistochemical evidence for the distribution of cGMP-accumulating neu rons in the brain of adult Xenopus. In most brain areas, the distribut ion of nNOS and cGMP immunoreactive structures (neuron somata and fibe rs) is distinct and separate, for instance in the dorsal pallium, the lateral thalamic nuclei, the optic tectum, the locus coeruleus and the reticular formation. However, nNOS and cGMP immunoreactive structures are often found in the vicinity of each other, and in the optic tectu m even in adjacent neuron fibers and somata. The present observations are in line with the presence of an NO-dependent soluble guanylate cyc lase in distinct brain areas of Xenopus laevis, corroborating similar data in the mammalian brain. Further, our observations may add to the understanding of the anatomical connectivity pattern and functional re levance of the NOergic system in the amphibian brain. (C) 1998 Elsevie r Science B.V. All rights reserved.