Dopaminergic regulation of cannabinoid receptor mRNA levels in the rat caudate-putamen: an in situ hybridization study.
By quantitative in situ hybridization, we examined in vivo in the rat caudate-putamen the effects on levels of cannabinoid receptor mRNA of an interruption of dopamine neurotransmission for up to 1 month, by either 6-hydroxydopamine lesioning of the medial forebrain bundle or dopamine receptor blockade. We found, in a first set of experiments, that unilateral 6-hydroxydopamine dopaminergic deafferentation of the striatum (characterized by a contralateral turning behavior in response to apomorphine, the almost complete disappearance of the tyrosine hydroxylase hybridization signal in the substantia nigra, and an increase of preproenkephalin A mRNA level in the striatum) was associated with significantly increased (45%) cannabinoid receptor mRNA levels in the homolateral caudate-putamen. In a second set of experiments, treatments with the dopamine D1 receptor antagonist SCH-23390, haloperidol, and the D2 receptor antagonist sulpiride induced significantly higher cannabinoid receptor mRNA levels (respectively, 67, 34, and 27%) in the caudate-putamen. These observations suggest for the first time that, in vivo, cannabinoid receptor gene expression in the caudate-putamen is under the negative control of dopamine receptor-mediated events.
Mailleux
P
P
Laboratory of Neurosciences, Université Libre de Bruxelles, Belgium.
Vanderhaeghen
J J
JJ
D000818:Animals; D001345:Autoradiography; D002421:Caudate Nucleus / Q000378:metabolism*; D003342:Corpus Striatum / Q000187:drug effects / Q000473:pathology; D004298:Dopamine / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects; D017403:In Situ Hybridization; D008297:Male; D008636:Mesencephalon / Q000378:metabolism; D016627:Oxidopamine / Q000633:toxicity; D011699:Putamen / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug / Q000096:biosynthesis* / Q000187:drug effects; D013462:Sulfur Radioisotopes; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis
D012333:RNA, Messenger; D043882:Receptors, Cannabinoid; D011955:Receptors, Drug; D013462:Sulfur Radioisotopes; D016627:Oxidopamine; D014446:Tyrosine 3-Monooxygenase; D004298:Dopamine