Beta 2- but not beta 1-adrenoceptors are involved in desipramine enhancement of aggressive behavior in long-term isolated mice.
The effects of several beta-adrenoceptor antagonists on the desipramine-induced increase in aggressive behavior in long-term isolated mice were examined. Desipramine HCl (10 mg/kg, IP) significantly increased the duration of aggressive behavior in isolated mice but did not significantly change the latency to the first attack consistent with our previous reports. Intraperitoneal administration of (+/- )propranolol HCl (2.5-10 mg/kg), a nonselective beta-adrenoceptor antagonist, dose dependently attenuated the desipramine-induced enhancement of aggressive behavior without significantly affecting the basal aggressive responses. ICI118,551 HCl (1.25-5 mg/kg, IP), a selective beta 2-adrenoceptor antagonist, also blocked the desipramine-induced enhancement of aggressive behavior in a dose-dependent manner, whereas metoprolol tartrate (5-20 mg/kg, IP), a selective beta 1-adrenoceptor antagonist, did not affect it. Moreover, clenbuterol HCl (0.1-0.5 mg/kg, IP), a lipophilic beta 2-adrenoceptor agonist, significantly increased the duration of basal aggressive behavior. Taken together with our previous finding that the desipramine-induced enhancement of aggressive behavior can be blocked by yohimbine, an alpha 2-adrenoceptor antagonist, the present results indicate that not only alpha 2- but also beta 2-adrenoceptor stimulation plays important roles in modulation of aggressive behavior in long-term isolated mice.
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CHEMICAL GENE-N GENE-Y GENE-N GENE-N GENE-Y GENE-Y GENE-Y GENE-Y CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL CHEMICAL
desipramine alpha 2-adrenoceptor beta 2-adrenoceptor beta-adrenoceptor beta-adrenoceptor beta 2-adrenoceptor beta 1-adrenoceptor beta 2-adrenoceptor beta 1-adrenoceptors desipramine yohimbine Desipramine HCl (+/- )propranolol HCl desipramine desipramine ICI118,551 HCl metoprolol tartrate clenbuterol HCl