Kalkman H O, Thoolen M J, Timmermans P B, van Zwieten P A
J Pharm Pharmacol. 1984 Apr;36(4):265-8. doi: 10.1111/j.2042-7158.1984.tb04365.x.
In pithed rats, but not in pithed cats, the alpha 2-/dopamine agonist B-HT 920 (10-300 micrograms kg-1) increased cardiac output. The increase was inhibited by yohimbine (1 mg kg-1), but not by sulpiride (0.3 mg kg-1) and nifedipine (1 mg kg-1). Both in pithed rats and cats, the alpha 1-adrenoceptor agonist methoxamine (30-300 micrograms kg-1 and 30-1000 micrograms kg-1, respectively) increased cardiac output. This increase (rats) was inhibited by prazosin (0.1 mg kg-1). The results indicate the existence of functional venous alpha 2-adrenoceptors in pithed rats, and their absence in pithed cats. Furthermore, alpha 2-adrenoceptor-mediated venoconstriction appears independent of extracellular calcium.
在脊髓横断的大鼠中，而非脊髓横断的猫中，α2/多巴胺激动剂B-HT 920（10 - 300微克/千克）可增加心输出量。这种增加被育亨宾（1毫克/千克）抑制，但未被舒必利（0.3毫克/千克）和硝苯地平（1毫克/千克）抑制。在脊髓横断的大鼠和猫中，α1肾上腺素能受体激动剂甲氧明（分别为30 - 300微克/千克和30 - 1000微克/千克）均可增加心输出量。这种增加（大鼠）被哌唑嗪（0.1毫克/千克）抑制。结果表明脊髓横断的大鼠中存在功能性静脉α2肾上腺素能受体，而脊髓横断的猫中不存在。此外，α2肾上腺素能受体介导的静脉收缩似乎与细胞外钙无关。
