Met-enkephalin and preproenkephalin mRNA changes in the striatum of the nicotine abstinence mouse.
We studied the changes of met-enkephalin (Met-Enk) content and preproenkephalin (PPE) mRNA in the striatum in a mouse model of nicotine abstinence. Nicotine, 2 mg/kg, s.c., was administered four times daily for 14 days and Met-Enk and PPE mRNA evaluated at various times (4-96 h) following drug discontinuation. Met-Enk, assayed by radioimmunoassay, was increased in the ventral (nucleus accumbens) but not dorsal (putamen/caudate) striatum, while PPE mRNA, assayed in whole striatum by Northern blotting was elevated. Both changes were seen early during withdrawal and lasted over 72 h. In situ hybridization revealed enhanced signal in the dorsal striatum, mostly laterally, and smaller increases in the rostral pole, core and shell of the nucleus accumbens. These observations indicate that during nicotine withdrawal, striatal enkephalinergic neurons undergo adaptative responses, which might contribute to the abstinence behavioral syndrome.
Isola
Raffaella
R
Department of Psychiatry, The Ohio State University School of Medicine and Public Health, 5034 Graves Hall, 333 West 10th Avenue, Columbus, OH 43210, USA.
Zhang
Hailing
H
Duchemin
Anne-Marie
AM
Tejwani
Gopi A
GA
Neff
Norton H
NH
Hadjiconstantinou
Maria
M
D000818:Animals; D001522:Behavior, Animal; D015152:Blotting, Northern; D003342:Corpus Striatum / Q000378:metabolism*; D004744:Enkephalin, Methionine / Q000235:genetics*; D004745:Enkephalins / Q000235:genetics*; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D009538:Nicotine / Q000009:adverse effects*; D009714:Nucleus Accumbens / Q000378:metabolism; D011498:Protein Precursors / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism*; D011863:Radioimmunoassay; D013375:Substance Withdrawal Syndrome / Q000378:metabolism* / Q000523:psychology; D013997:Time Factors; D014018:Tissue Distribution
D004745:Enkephalins; D011498:Protein Precursors; D012333:RNA, Messenger; D004744:Enkephalin, Methionine; D009538:Nicotine; C033660:preproenkephalin