Morphine alters preproenkephalin gene expression.
Rats made tolerant/dependent to morphine by s.c. implantation of drug pellets displayed a significant decrease in striatal preproenkephalin mRNA that persisted during the period of withdrawal. Levels of Met-enkephalin were normal at the end of treatment, but reduced after withdrawal. The direction and time-course of these alterations are consistent with roles for altered neuronal gene expression in the phenomena of opiate tolerance and dependence.
Uhl
G R
GR
Gene Neuroscience Unit, ARC, NIDA, Baltimore, MD 21224.
Ryan
J P
JP
Schwartz
J P
JP
D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004343:Drug Implants; D004744:Enkephalin, Methionine / Q000235:genetics / Q000378:metabolism; D004745:Enkephalins / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009693:Nucleic Acid Hybridization; D011498:Protein Precursors / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013375:Substance Withdrawal Syndrome
D004343:Drug Implants; D004745:Enkephalins; D011498:Protein Precursors; D012333:RNA, Messenger; D004744:Enkephalin, Methionine; D009020:Morphine; C033660:preproenkephalin