Effects of mecamylamine on flash-evoked potentials, body temperature, and behavior in Long-Evans rats.
This experiment examined the effects of mecamylamine, a nicotinic acetylcholine receptor antagonist, on flash-evoked potentials (FEPs) recorded from the visual cortex (VC) and superior colliculus (SC) of chronically implanted male Long-Evans rats, and on body temperature and open field behavior. FEPs were recorded at 20 and 35 min following intraperitoneal injections of saline, and of 0.3, 3.0, and 10.0 mg/kg mecamylamine on separate days. The 0.3 mg/kg dose did not produce significant effects. The amplitude of VC components N₃₀, P₄₈, and P₈₇ increased, N₁₅₀ and P₂₃₁ decreased, and P₂₃, N₄₀, N₅₈, and N₆₈ were unchanged following administration of the 10.0 mg/kg dose. In the SC, component P₂₈ was unaffected, P₃₉ was reduced, and N₄₉ was augmented by the 10.0 mg/kg dose. All component peak latencies were increased by the 3.0 and 10.0 mg/kg doses. Significant hypothermia was also produced by the 3.0 and 10.0 mg/kg doses, suggesting that this was the basis for the increased latencies. The 10.0 mg/kg dose produced a significant decrease in movement during the recording sessions. In subsequent open field observations, both line crossings and rearings were reduced by the 3.0 and 10.0 mg/kg doses. The results suggest that endogenous acetylcholine acting on nicotinic acetylcholine receptors plays at most a modest role in producing FEPs recorded from the VC and SC.
Department of Psychology, Lawrence University, 711 E. Boldt Way, Appleton, WI 54911, USA. hetzlerb@lawrence.edu
Bruce E
BE
Hetzler
Elizabeth J
EJ
Beckman
D000818:Animals; D001831:Body Temperature / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005074:Evoked Potentials, Visual / Q000187:drug effects*; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology*; D051381:Rats; D020318:Rats, Long-Evans
D008464:Mecamylamine