可乐定(ctonidine)为一中枢性降压药,目前认为其降压作用原理在于兴奋延脑孤束核次一级神经元的突触后膜a_2受体(这个神经元是抑制性神经元),使外周交感神经受到抑制而导致血压下降。此外,可乐定对外周肾上腺素能神经元突触前膜a_2受体也有激动作用,由此引起负反馈。使末稍去甲肾上腺素释放减少而发挥降压作用。晚近发现尚具有镇静、降温、抗焦虑、抑制胃酸分泌等作用,临床上报道可用于抗惊厥、预防 Corydal (ctonidine) is a central antihypertensive drug, now that the principle of its antihypertensive effect is excited at the seminiferous tubules nucleus a postsynaptic membrane a_2 receptors (this neuron is inhibitory neurons) , The peripheral sympathetic nerve is suppressed and lead to decreased blood pressure. In addition, clonidine also had an agonistic effect on the presynaptic membrane a_2 receptor in peripheral adrenergic neurons, which led to negative feedback. The final release of norepinephrine play a role in antihypertensive effect. Recently found that there is still sedative, cooling, anti-anxiety, inhibition of gastric acid secretion and other clinical reports can be used for anticonvulsant, prevention