Local mu and delta opioid receptors regulate amphetamine-induced behavior and neuropeptide mRNA in the striatum.
The purpose of this study was to investigate the role that mu and delta opioid receptor blockade has upon stimulant-induced behavior and neuropeptide gene expression in the striatum. Acute administration of amphetamine (2.5 mg/kg i.p.) caused an increase in behavioral activity and preprodynorphin, substance P, and preproenkephalin mRNA expression. Intrastriatal infusion of the mu opioid antagonist, H-D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH(2) (CTAP), or the delta opioid antagonist, H-Tyr-Tic[CH(2)NH]-Phe-Phe-OH (TIPPpsi), significantly decreased amphetamine-induced vertical activity. However, only CTAP reduced amphetamine-induced distance traveled. Quantitative in situ hybridization histochemistry revealed that CTAP blocked amphetamine-induced preprodynorphin and substance P mRNA. However, preproenkephalin mRNA levels in the dorsal striatum were increased to the same extent by CTAP, amphetamine, or a combination of the two drugs. In contrast, TIPPpsi significantly decreased amphetamine-induced mRNA expression of all three neuropeptides. These data indicate that both mu and delta receptor subtypes differentially regulate amphetamine-induced behavior and neuropeptide gene expression in the rat striatum.
Gonzalez-Nicolini
M V
MV
Department of Physiology and Neuroscience, Medical University of South Carolina, 173 Ashley Avenue, BSB 403, Charleston, SC 29425, USA.
Berglind
W
W
Cole
K S
KS
Keogh
C L
CL
McGinty
J F
JF
D000661:Amphetamine / Q000494:pharmacology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D004347:Drug Interactions; D017403:In Situ Hybridization; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009292:Narcotic Antagonists / Q000494:pharmacology; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology; D010446:Peptide Fragments; D010455:Peptides / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D011856:Radiographic Image Enhancement; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D017465:Receptors, Opioid, delta / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D017450:Receptors, Opioid, mu / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000502:physiology; D013004:Somatostatin
C529311:CTAP octapeptide; D000697:Central Nervous System Stimulants; D009292:Narcotic Antagonists; D009479:Neuropeptides; D009842:Oligopeptides; D010446:Peptide Fragments; D010455:Peptides; D012333:RNA, Messenger; D017465:Receptors, Opioid, delta; D017450:Receptors, Opioid, mu; C092721:tyrosyl-tetrahydroisoquinolinecarbonyl-psi(methylamino)phenylalanyl-phenylalanine; D013004:Somatostatin; D000661:Amphetamine