Expression of dopamine D2 receptor and choline acetyltransferase mRNA in the dopamine deafferented rat caudate-putamen.
In situ hybridization was used to study dopamine D2 receptor (D2R) and choline acetyltransferase (ChAT) mRNA expression in neurons of the rat forebrain, both on control animals and after a unilateral 6-hydroxydopamine (6-OHDA) lesion of midbrain dopamine neurons. D2R mRNA expressing neurons were seen in regions which are known to be heavily innervated by midbrain dopamine fibers such as caudate-putamen, nucleus accumbens and olfactory tubercle. ChAT mRNA expressing neurons were seen in caudate-putamen, nucleus accumbens and septal regions including vertical limb of the diagonal band. In caudate-putamen, approximately 55% of the medium sized neurons, which is the predominating neuronal cell-size in this region, were specifically labeled with the D2R probe. In addition, approximately 95% of the large size neurons in caudate-putamen were specifically labeled with both the D2R and ChAT probes, suggesting that most cholinergic neurons in the caudate-putamen express D2R mRNA. After a unilateral lesion of midbrain dopamine neurons, no change in the level of either D2R or ChAT mRNA were seen in the large size intrinsic cholinergic neurons in caudate-putamen. Similarly, no evidence was obtained for altered levels of D2R mRNA in medium size neurons in medial caudate-putamen, or nucleus accumbens. However, an increase in the number of medium size neurons expressing D2R mRNA was observed in the lateral part of the dopamine deafferented caudate-putamen. Thus, it appears that midbrain dopamine deafferentation causes an increase in D2R mRNA expression in a subpopulation of medium size neurons in the lateral caudate-putamen.
Brené
S
S
Department of Medical Chemistry, Karolinska Institute, Stockholm, Sweden.
Lindefors
N
N
Herrera-Marschitz
M
M
Persson
H
H
D000595:Amino Acid Sequence; D000818:Animals; D002421:Caudate Nucleus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002795:Choline O-Acetyltransferase / Q000235:genetics*; D003714:Denervation; D004298:Dopamine / Q000494:pharmacology; D015870:Gene Expression; D008297:Male; D008969:Molecular Sequence Data; D009474:Neurons / Q000378:metabolism; D009475:Neurons, Afferent; D011699:Putamen / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis*; D051381:Rats; D011954:Receptors, Dopamine / Q000032:analysis* / Q000235:genetics; D017448:Receptors, Dopamine D2
D012333:RNA, Messenger; D011954:Receptors, Dopamine; D017448:Receptors, Dopamine D2; D002795:Choline O-Acetyltransferase; D004298:Dopamine