Evidence that weaning stimulates the developmental expression of a delta-opioid receptor subtype in the rat.
To study whether weaning stimulates the development of a subtype of the delta-opioid receptor we have measured antinociceptive activity of putative delta 1 (DELT I) and delta 2 (DSLET) agonists in weaned and non-weaned 25-day-old rats. In weaned rats, DSLET produced antinociception reversed by the delta 2-antagonist naltriben, but in non-weaned rats DSLET had no effect. Responses to DELT I were evident in both weaned and non-weaned rats and were not antagonised by naltriben. This is the first evidence that delta-receptor subtypes develop independently and suggests that weaning is the stimulus for the expression of the delta 2-subtype.
Kitchen
I
I
Receptors and Cellular Regulation Research Group, School of Biological Sciences, University of Surrey, Guildford, UK.
Crook
T J
TJ
Muhammad
B Y
BY
Hill
R G
RG
D000700:Analgesics / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D008297:Male; D009271:Naltrexone / Q000031:analogs & derivatives / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D009842:Oligopeptides / Q000037:antagonists & inhibitors / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017465:Receptors, Opioid, delta / Q000096:biosynthesis* / Q000187:drug effects; D014886:Weaning
D000700:Analgesics; D009292:Narcotic Antagonists; D009842:Oligopeptides; D017465:Receptors, Opioid, delta; C068868:naltrindole benzofuran; C060208:deltorphin I, Ala(2)-; D004743:Enkephalin, Leucine; D009271:Naltrexone; C034318:enkephalin, Ser(2), Leu(5), Thr(6)-