Strain differences to the effects of apomorphine on Sidman avoidance response and motor activity in the Wistar and F344/DuCrj (Fischer) rats.
The effects of apomorphine HCl (APM), a direct dopamine agonist, on Sidman avoidance response (response-shock interval = 30 see and shock-shock interval = 5 sec) and on motor activity in Wistar and F344/DuCrj (Fischer) male rats were examined to investigate the role of dopaminergic systems in differences between the two strains. APM 0.025 mg/kg sc tended to suppress the avoidance response in both strains. APM 0.2-0.8 mg/kg sc increased the response rate and tended to decrease the shock rate in the Fischer rats. In contrast, the same doses of APM did not induce a marked change in the response rate but did induce a prominent increase in the shock rate in the Wistar rats. APM 0.2-0.8 mg/kg sc produced stereotypy such as sniffing, licking, and gnawing in both Wistar and Fischer rats. There was no strain difference in the APM-induced stereotypy, but only the Fischer rats exhibited ambulatory movement (locomotion) after APM 0.2-0.8 mg/kg sc The present results suggest that the Wistar and Fischer rats respond differently to APM in terms of conditioned avoidance response and motor activity as indices of the drug effect.
D000818:Animals; D001058:Apomorphine / Q000008:administration & dosage / Q000494:pharmacology*; D001362:Avoidance Learning / Q000187:drug effects*; D003216:Conditioning, Operant / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D051381:Rats; D011916:Rats, Inbred F344; D011919:Rats, Inbred Strains
D001058:Apomorphine