Effects of cabergoline and rotigotine on tacrine-induced tremulous jaw movements in rats.

Abstract Objectives We examined the effects of two dopamine agonists, cabergoline and rotigotine, on tacrine-induced tremor and c-Fos expression in rats. Methods Rats received intraperitoneal injection of cabergoline (0.5, 1.0, or 5.0 mg/kg), rotigotine (1.0, 2.5, or 10.0 mg/kg), or vehicle 30 min before intraperitoneal injection of tacrine (5.0 mg/kg). The number of tremulous jaw movements (TJMs) after tacrine administration was counted for 5 min. Animals were sacrificed 2 h later under deep anesthesia, and the brain sections were immunostained in order to evaluate the c-Fos expression. Results Induction of TJMs by tacrine was dose-dependently reduced by pretreatment with cabergoline and rotigotine. The number of c-Fos-positive cells was significantly enhanced in the medial striatum, nucleus accumbens core, and nucleus accumbens shell after tacrine administration, and the enhanced expression of c-Fos in these three regions was significantly attenuated by cabergoline, while rotigotine suppressed c-Fos expression in two regions except the nucleus accumbens core. Conclusions These results suggest that tacrine-induced TJMs would be relieved by either cabergoline or rotigotine and that anticholinesterase-induced TJMs and the ameliorating effects of dopamine agonists would relate to neuronal activation in the striatum and nucleus accumbens.