caa a22 4500 46907969X CHVBK 20180323132946.0 cr unu---uuuuu 170328e19920501xx s 000 0 eng 10.1007/BF00168948 doi (NATIONALLICENCE)springer-10.1007/BF00168948 Coupar Ian Unit of Additive Drug Research, School of Pharmacology, Victorian College of Pharmacy, 381 Royal Parade, 3052, Parkville, Victoria, Australia aut Effect of α2-adrenoceptor agonists on the expression of morphine-withdrawal in rats [Elektronische Daten] [Ian Coupar] Summary: Previous studies using clonidine indicate that α2-adrenoceptors are involved in suppressing opiate-withdrawal symptoms. However, clonidine may act as a partial agonist at α2-adrenoceptors and it also possesses significant α1-receptor agonist activity. The aim of this study was to determine the role of α2-adrenoceptors in the expression of opiate withdrawal signs using morphine-dependent rats. A range of agonists were selected for study on the basis of their differential preferences for α-adrenoceptors. Hooded Wistar rats were made physically dependent on morphine (s.c. injection of an emulsion releasing a total of 250 mg/kg of morphine base over 48 h). Test drugs were injected s.c. followed by naloxone (10 mg/kg i.p.) 20 min later. The incidence of 5 selected withdrawal signs was recorded during the following 20 min. The α2-adrenoceptor agonists displayed different profiles of activity. Azepexole (1-10 mg/kg) reduced all signs. Clonidine (80-800 μg/kg) reduced all signs except paw shakes while guanfacine (25-250 μg/kg) reduced all except jumping and diarrhoea. Talipexole (0.1-1 mg/kg) reduced all signs except diarrhoea which was not affected and jumping which was markedly enhanced. UK 14,304 (80-800 μg/kg) reduced jumps, potentiated paw shakes but did not affect body shakes, teeth chattering or diarrhoea. The results suggest that there are subpopulations of α2-adrenoceptors that modulate the expression of opiate withdrawal signs and/or that some of the drugs used affect receptors other than α2-adrenoceptors. Springer-Verlag, 1992 Opiate addiction nationallicence Morphine withdrawal nationallicence α2-adrenoceptor agonists nationallicence Clonidine nationallicence Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 345/5(1992-05-01), 553-557 0028-1298 345:5<553 1992 345 210 https://doi.org/10.1007/BF00168948 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00168948 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Coupar Ian Unit of Additive Drug Research, School of Pharmacology, Victorian College of Pharmacy, 381 Royal Parade, 3052, Parkville, Victoria, Australia aut NATIONALLICENCE 773 0- Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 345/5(1992-05-01), 553-557 0028-1298 345:5<553 1992 345 210 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer