Characterization of striatal neurons expressing high levels of glutamic acid decarboxylase messenger RNA.
Two types of labelled cells are detected in sections of rat and mouse striata processed for in situ hybridization histochemistry with 35S-radiolabelled RNA probes complementary to the messenger RNA (mRNA) encoding glutamic acid decarboxylase (GAD), the synthesis enzyme for gamma-aminobutyric acid (GABA): numerous lightly, and fewer very densely labelled neurons. In order to determine whether the densely labelled cells correspond to the striatal somatostatinergic neurons with which they share morphological characteristics, the presence of GAD mRNA was examined in brain sections processed successively for dihydronicotinamide adenine dinucleotide phosphate (NADPH) diaphorase histochemistry, a marker of striatal somatostatinergic neurons, and in situ hybridization histochemistry. In addition, the distribution of GABAergic interneurons was analyzed with regard to striatal compartments (striosomes) indicated by patches of dense opiate binding sites. The results show that NADPH diaphorase activity and GAD mRNA do not co-exist in striatal neurons. Furthermore, in contrast to the somatostatinergic neurons which are almost exclusively located in the extrastriosomal matrix, densely labelled GAD cells were present both in the striosomes and the matrix, further suggesting that GABAergic and somatostatinergic neurons form two distinct interneuronal systems in the striatum of rats and mice.
Chesselet
M F
MF
Department of Pharmacology, Medical College of Pennsylvania, EPPI, Philadelphia 19129.
Robbins
E
E
D000818:Animals; D003342:Corpus Striatum / Q000166:cytology / Q000378:metabolism*; D004723:Endorphins / Q000378:metabolism; D005968:Glutamate Decarboxylase / Q000378:metabolism*; D051379:Mice; D009252:NADPH Dehydrogenase / Q000378:metabolism; D009693:Nucleic Acid Hybridization; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D013004:Somatostatin / Q000378:metabolism
D004723:Endorphins; D012333:RNA, Messenger; D013004:Somatostatin; D009252:NADPH Dehydrogenase; D005968:Glutamate Decarboxylase