Hancock J C, Hoover D B
Arch Int Pharmacodyn Ther. 1984 Jun;269(2):295-303.
Experiments were conducted in anesthetized rats to determine the effect of unilateral carotid artery occlusion on the reflex bradycardia caused by elevated arterial pressure (AP) and on clonidine's ability to potentiate that bradycardia. AP was recorded by catheterizing the carotid (CA-cath) or the iliac (IA-cath) artery. Elevated AP was obtained by rapid intravenous injection of methoxamine. Rats with CA-cath had higher APs and heart rates (HRs) than rats with IA-cath. The maximum increase in AP and reflex decrease in HR caused by methoxamine did not differ between sites of recording. Clonidine markedly increased the reflex bradycardia in rats with IA-cath. The reflex decrease in HR caused by methoxamine was not potentiated by clonidine in rats with either CA-cath or IA-cath with the CA clamped or following chemical denervation of the carotid sinus area with phenol. It is concluded that while unilateral carotid artery occlusion does not alter the reflex response to elevations in AP, it significantly interferes with clonidine's ability to potentiate baroreceptor responses.
在麻醉大鼠身上进行实验，以确定单侧颈动脉闭塞对动脉压（AP）升高引起的反射性心动过缓以及可乐定增强该心动过缓能力的影响。通过将导管插入颈动脉（CA - 导管）或髂动脉（IA - 导管）来记录AP。通过快速静脉注射甲氧明来升高AP。使用CA - 导管的大鼠比使用IA - 导管的大鼠具有更高的AP和心率（HR）。甲氧明引起的AP最大增加和HR反射性降低在记录部位之间没有差异。可乐定显著增加了使用IA - 导管的大鼠的反射性心动过缓。在CA夹住的使用CA - 导管或IA - 导管的大鼠中，或者在用苯酚对颈动脉窦区域进行化学去神经支配后，可乐定并未增强甲氧明引起的HR反射性降低。得出的结论是，虽然单侧颈动脉闭塞不会改变对AP升高的反射反应，但它会显著干扰可乐定增强压力感受器反应的能力。
