Dopamine-dependent behavioural stimulation by non-peptide delta opioids BW373U86 and SNC 80: 1. Locomotion, rearing and stereotypies in intact rats.
The unconditioned behavioural effects of two non-peptide delta-opioid receptor agonists, BW 373U86 and SNC 80, were studied in the intact rat. BW 373U86 (0.1-2.5 mg/kg s.c.) and SNC 80 (2.5-10 mg/kg s.c.) dose-dependently elicited locomotion, rearing, stereotyped sniffing, licking and gnawing. These effects were abolished by pretreatment with the delta-opioid receptor antagonist naltrindole (5.0 mg/kg s.c.). In view of the phenomenological similarities between this syndrome and that elicited by dopamine-receptor agonists, the role played by dopamine receptors was investigated. The specific dopamine D1 receptor antagonist SCH 23390 and the specific dopamine D2/D3 receptor antagonist raclopride reduced or even abolished the behavioural stimulation induced by lower doses of BW 373U86 and SNC 80. When higher doses of BW 373U86 were used (2.5 mg/kg), however, raclopride, even at high cataleptic doses (6.0 mg/kg), only partly prevented the behavioural stimulation induced by the delta-opioid receptor agonist. The behavioural stimulation remaining after high doses of raclopride was abolished by the administration of SCH 23390. These results show that delta-opioid receptor stimulation elicits dopamine-dependent behavioural activation in the rat that depends on dopamine receptors, particularly of the D1 subtype.
Spina
L
L
Department of Toxicology, University of Cagliari, Italy.
Longoni
R
R
Mulas
A
A
Chang
K J
KJ
Di Chiara
G
G
D000818:Animals; D001549:Benzamides / Q000494:pharmacology*; D001552:Benzazepines / Q000494:pharmacology; D004298:Dopamine / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D010879:Piperazines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017465:Receptors, Opioid, delta / Q000819:agonists*; D013239:Stereotyped Behavior / Q000187:drug effects*; D013997:Time Factors
D001549:Benzamides; D001552:Benzazepines; D010879:Piperazines; D017465:Receptors, Opioid, delta; C083877:BW 373U86; C088464:4-(alpha-(4-allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl)-N,N-diethylbenzamide; D004298:Dopamine