Yamada S, Yamamura H I, Roeske W R
Naunyn Schmiedebergs Arch Pharmacol. 1982 Aug;320(2):115-8. doi: 10.1007/BF00506311.
Chronic treatment (22 days) of rats with clonidine (0.5 mg/kg s.c. twice a day followed by 20 h of withdrawal) resulted in a significant increase in the specific [3H]WB4101 binding to ventricular and intraventricular septal alpha 1-adrenoceptors but no alteration of the atrial alpha 1-adrenoceptors. Scatchard analysis indicated that the increase in the [3H]WB4101 binding to the clonidine-treated cardiac tissue was due to an enhancement of the alpha 1-adrenoceptor density since there was a significant increase in the Bmax value for the [3H]WB4101 binding to the treated ventricles without a change in the Kd value. The specific [3H]WB4101 binding to cardiac alpha 1-adrenoceptors was not altered by the acute (1 day) or 7 days treatment with clonidine. Chronic treatment with clonidine had no significant effect on the specific 3HDHA binding to the atrial and ventricular beta-adrenoceptor. The noradrenaline (NA) concentrations in the clonidine-treated ventricles and intraventricular septae were decreased by 16-20%. These data provide biochemical evidence compatible with a significant reduction of sympathetic outflow to the ventricular myocardium by clonidine.
用可乐定对大鼠进行慢性治疗（22天，每天皮下注射0.5毫克/千克，分两次给药，随后停药20小时），导致心室和室间隔α1 - 肾上腺素能受体的特异性[3H]WB4101结合显著增加，但心房α1 - 肾上腺素能受体无变化。Scatchard分析表明，可乐定处理的心脏组织中[3H]WB4101结合增加是由于α1 - 肾上腺素能受体密度增强，因为与处理过的心室的[3H]WB4101结合的Bmax值显著增加，而Kd值无变化。急性（1天）或7天可乐定处理未改变心脏α1 - 肾上腺素能受体的特异性[3H]WB4101结合。可乐定慢性治疗对心房和心室β - 肾上腺素能受体的特异性3HDHA结合无显著影响。可乐定处理的心室和室间隔中的去甲肾上腺素（NA）浓度降低了16 - 20%。这些数据提供了生化证据，表明可乐定可显著减少对心室心肌的交感神经输出。
