D1 AND D2 DOPAMINE-RECEPTOR GENE-EXPRESSION IN THE RAT STRIATUM – SENSITIVE CRNA PROBES DEMONSTRATE PROMINENT SEGREGATION OF D1 AND D2 MESSENGER-RNAS IN DISTINCT NEURONAL POPULATIONS OF THE DORSAL AND VENTRAL STRIATUM
J. Comp. Neurol.. 1995-05-08; 355(3): 418-426
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1. J Comp Neurol. 1995 May 8;355(3):418-26.
D1 and D2 dopamine receptor gene expression in the rat striatum: sensitive cRNA
probes demonstrate prominent segregation of D1 and D2 mRNAs in distinct neuronal
populations of the dorsal and ventral striatum.
Le Moine C(1), Bloch B.
(1)Laboratoire d’Histologie-Embryologie, EP CNRS 74, Université de Bordeaux II,
The postsynaptic effects of dopamine in the striatum are mediated mainly by
receptors encoded by D1, D2, and D3 dopamine receptor genes. The D1 and D2 genes
are the most widely expressed in the caudate-putamen, the accumbens nucleus, and
the olfactory tubercle. Several anatomical studies, including studies using in
situ hybridization with oligonucleotide and cDNA probes, have suggested that D1
and D2 receptors are segregated into distinct efferent neuronal populations of
the striatum: D1 in substance P striatonigral neurons and D2 in enkephalin
striatopallidal neurons. In contrast, on the basis of several in vivo and in
vitro studies, other authors have suggested the existence of an extensive
colocalization of D1 and D2 in the same striatal neurons. Our study was
undertaken in order to analyze in detail the expression of the D1 and D2 receptor
genes in the efferent striatal populations, with special reference to the various
striatal areas, and to yield insights into the question about D1 and D2 mRNA
localization in the striatum. We have, therefore, used highly sensitive
digoxigenin- and 35S-labeled cRNA probes to address this question. The present
results demonstrate that the D1 and D2 receptor mRNAs are segregated,
respectively, in substance P and enkephalin neurons in the caudate-putamen and
accumbens nucleus (shell and core) and in the olfactory tubercle (for their
largest part). A very small percentage of neurons may coexpress both genes. These
results confirm that the D1 and D2 receptor genes are expressed in distinct
populations of striatal efferent neurons in the normal adult rat.
PMID: 7636023 [Indexed for MEDLINE]