Go Koganemaru1, Hiroshi Abe2, Aki Kuramashi1, Kosuke Ebihara1, Hisae Matsuo1, Hideki Funahashi1, Kazuya Yasuda3, Tetsuya Ikeda4, Toshikazu Nishimori1, Yasushi Ishida1. 1. Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-city, Miyazaki 889-1692, Japan. 2. Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-city, Miyazaki 889-1692, Japan. Electronic address: abehiro@med.miyazaki-u.ac.jp. 3. Department of Psychiatry, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-city, Miyazaki 889-1692, Japan; Department of Pharmacy, Faculty of Medicine, University of Miyazaki Hospital, 5200 Kihara, Kiyotake, Miyazaki-city, Miyazaki 889-1692, Japan. 4. Division of Neurobiology, Faculty of Medicine, University of Miyazaki, 5200 Kihara, Kiyotake, Miyazaki-city, Miyazaki 889-1692, Japan.
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 5.0mg/kg), rotigotine (1.0, 2.5, or 10.0mg/kg), or vehicle 30min before intraperitoneal injection of tacrine (5.0mg/kg). The number of tremulous jaw movements (TJMs) after tacrine administration was counted for 5min. Animals were sacrificed 2h 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.
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 5.0mg/kg), rotigotine (1.0, 2.5, or 10.0mg/kg), or vehicle 30min before intraperitoneal injection of tacrine (5.0mg/kg). The number of tremulous jaw movements (TJMs) after tacrine administration was counted for 5min. Animals were sacrificed 2h 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.