Cocaine self-administration differentially alters mRNA expression of striatal peptides.
The influence of cocaine self-administration on the expression of messenger RNAs for dynorphin, enkephalin and substance P was analyzed in the rat striatum with in situ hybridization histochemistry. Cocaine, an indirect dopamine agonist, was found to differentially affect the levels of mRNA encoding these neuropeptides in different subregions of the striatum. Following a 7 day period of variable free access to cocaine, dynorphin and substance P mRNA levels were elevated throughout the striatum, but the increases were substantially greater in the dorsal striatum than in the nucleus accumbens. Enkephalin mRNA was not significantly altered in the dorsal striatum but was slightly elevated in the nucleus accumbens. These results suggest that cocaine self-administration has differential effects on striatonigral and striatopallidal projection neurons, and that these effects vary in subregions of the striatum.
Hurd
Y L
YL
Laboratory of Cell Biology, National Institute of Mental Health, Bethesda, MD 20892.
Brown
E E
EE
Finlay
J M
JM
Fibiger
H C
HC
Gerfen
C R
CR
D000818:Animals; D001345:Autoradiography; D002421:Caudate Nucleus / Q000502:physiology; D003042:Cocaine / Q000008:administration & dosage / Q000494:pharmacology*; D003342:Corpus Striatum / Q000187:drug effects / Q000502:physiology*; D003838:Deoxyadenine Nucleotides; D004399:Dynorphins / Q000235:genetics*; D004745:Enkephalins / Q000235:genetics*; D015870:Gene Expression / Q000187:drug effects; D008297:Male; D015345:Oligonucleotide Probes; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D012016:Reference Values; D012646:Self Administration; D013373:Substance P / Q000235:genetics*; D013462:Sulfur Radioisotopes
D003838:Deoxyadenine Nucleotides; D004745:Enkephalins; D015345:Oligonucleotide Probes; D012333:RNA, Messenger; D013462:Sulfur Radioisotopes; D013373:Substance P; D004399:Dynorphins; D003042:Cocaine; C026600:2'-deoxyadenosine triphosphate