Alternate coexistence of NADPH-diaphorase with choline acetyltransferase or somatostatin in the rat neostriatum and basal forebrain.

Abstract

The coexistence of reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) with somatostatin (SOM) and choline acetyltransferase (ChAT) was compared between the rat neostriatum (ST) and basal forebrain complex (BF). NADPH-d coexists with SOM in ST, but not in the ventral pallidum (VP), in the substantia innominata-nucleus basalis complex (SI-NB) and in the magnocellular preoptic nucleus (NPM) of the BF. In the medial septal nucleus as well as in the vertical and the horizontal limbs of the diagonal band (MS-vDB, hDB) representing the rostral BF and in the SI-NB, a high number of ChATpositive cells also contain NADPH-d. The NPM shows a smaller number of double-stained cholinergic neurons. The functional significance of the NADPH-d coexistence in BF cholinergic cells is still unknown.Whereas the NADPH-d is known to coexist with SOM in a population of interneurons distributed throughout the rat ST, the cholinergic interneurons of this region constantly show negative reactions after treatment according to the NADPH-d histochemistry (15,17). In the BF, where the cholinergic cells represent the predominant neuronal component (2, 8) the occurrence of SOM containing cells is restricted to some parts of this unhomogeneous region (1). In the present study we follow the questions: a) Do SOM and ChAT immunoreactive neurons occur with coexisting NADPH-d in the rat BF? b) Are there regional differences in the distribution of double-and single-labelled cells in the BF? MATERIALS AND METHODSWistar rats were anaesthetized and perfused transcardially with a fixative of 4% paraformaldehyde in 0.1M phosphate buffer (PB), pH 7.4. After removing the brains an immersion fixation of 12hr followed. The forebrains were dissected out Address reprint requests to:

Rabbit forebrain cholinergic system: Morphological characterization of nuclei and distribution of cholinergic terminals in the cerebral cortex and hippocampus

“…Interestingly, cholinergic interneurons were frequently seen in the hippocampus but were scarce in neocortical areas. Analysis of the neurochemical heterogeneity of cholinergic cell populations in rabbit BFB revealed the sparse occurrence of CB (ϳ19%) and nNOS (Ͻ1%) in cholinergic neurons of posterior MBN, a finding that provides a phylogenetic niche for the rabbit forebrain cholinergic system between rodents (with partial nNOS coexpression; Schober et al, 1989;Brauer et al, 1991;Geula et al, 1993) and primates (with partial CB coexpression; Chang and Kuo, 1991;Côté and Parent, 1992;Geula et al, 1993;Ichitani et al, 1993;Hä rtig et al, 2002). This assumption is further supported by recent phylogenetic concepts indicating that the rabbit, a member of the mammalian order Lagomorpha, has a distant relationship to members of the orders of both Rodentia and Primates (Benton, 2000).…”

“…In the rat, distinct subpopulations of cholinergic projection neurons are immunoreactive for nNOS (Schober et al, 1989;Brauer et al, 1991;Geula et al, 1993). In contrast, nNOS is entirely absent in cholinergic projection cells of primates (Geula et al, 1993;Wu et al, 2000), where ChAT-and nNOS-positive neurons form nonoverlapping populations throughout the "Ch1"-"Ch4" regions.…”

“…These include, for example, the relative reduction of MS and VDB; appearance of septum pellucidum; topological organization of the VP and the MBN/SI complex; and localization of the capsulae interna, externa, and extrema. From a neurochemical point of view, 1) selective expression of the low-affinity neurotrophin receptor p75 (p75 NTR ) in cholinergic neurons of all mammalian species (Mufson et al, 1989;Maclean et al, 1997; (Chang and Kuo, 1991;Côté and Parent, 1992;Geula et al, 1993;Ichitani et al, 1993;Hä rtig et al, 2002); and 3) coexpression of neuronal (constitutive) nitric oxide synthase (nNOS) in subsets of rat BFB cholinergic neurons (Schober et al, 1989;Brauer et al, 1991;Geula et al, 1993) illustrate profound phylogenetic differences that may substantially influence the sensitivity of cholinergic neurons of different mammalian species to aging and to experimental manipulations. Recent experimental data indicate that the rabbit brain might be in several respects appropriate for modeling multiple neurochemical characteristics of AD, inasmuch as subcortical denervation by means of ME20.4-saporin induced selective cholinergic immunolesions (Beach et al, 2000), and feeding with diets containing high cholesterol concentrations was shown to trigger the formation of senile plaque-like ␤-amyloid deposits in the rabbit cerebral cortex (Sparks et al, 1994(Sparks et al, , 1995(Sparks et al, , 2000.…”

NADPH‐diaphorase active and calbindin D‐28k‐immunoreactive neurons and fibers in the olfactory bulb of the hedgehog (Erinaceus europaeus)

“…Previous studies in different regions of the rat brain have shown that ND is expressed by neurons containing acetylcholine (Vincent et al, 1983b,c;Vincent, 1986;Schober et al, 1989); y-aminobutyric acid (GABA) (Vaney and Young, 1988;Hedlich et al, 1990); enkephalins (Roberts and Difiglia, 1988); somatostatin (Vincent et al, 1983a;Vincent, 1986;Scott et al, 1987;Sharp et al, 1987;Alonso et al, 1992b); neuropeptide Y, C-PON, and avian pancreatic polypeptide (Vincent et al, 1983a;Scott et al, 1987;Villalba et al, 1988Villalba et al, , 1989; calretinin ; and CaBP (Alonso et al, 1992a. However, for all these substances there are only regional or partial overlaps and coexpressions, and the unique general coexistence is with nitric oxide synthase (Dawson et al, 19911, and with citrulline, a byproduct in nitric oxide synthesis (Hope et al, 1991).…”

Morphology and distribution patterns of galanin immunoreactive axons in the rat basal forebrain comparison with the distribution patterns of GAD immunoreactive axons.

“…One of these cholinergic subpopulations in the rostral BF is the outer assembly of cholinergic cells near the margin between hDB and VP. These cells have never shown coexpression of NADPHdiaphorase histochemistry (16), contrary to other cholinergic subpopulations where double-labelling occurs. It cannot be excluded that not yet known functional interrelations with regard to these findings and the specificity of galanin containing fibre innervation may exist.…”