Krassioukov A V, Gelb A W, Weaver L C
Department of Stroke and Aging, John P. Robarts Research Institute, University of Western Ontario, London.
Can J Anaesth. 1995 Feb;42(2):150-7. doi: 10.1007/BF03028269.
Tonic firing of pontine neurons provides excitatory input to the vasomotor centre in the ventrolateral medulla. To increase our understanding of the actions of propofol on CNS neurons controlling the cardiovascular system, we evaluated the effects of propofol on this tonic firing of pontine neurons. The actions of propofol (doses 1-4, respectively: 24 +/- 2, 40 +/- 4, 65 +/- 3 and 104 +/- 3 mg.kg-1.hr-1) on the pontine neurons were studied using eight atropinized Wistar rats. Electrical activity of renal sympathetic nerves, systemic arterial blood pressure and heart rate were recorded. Propofol decreased renal nerve activity by 3 +/- 2%, 23 +/- 3%, 33 +/- 3% and 52 +/- 4% at the four doses. Arterial pressure and heart rate decreased similarly in a dose-dependent manner. Sympathetic and cardiovascular responses to blocking neurons in the pontine reticular formation by microinjection of glycine were depressed by propofol. Renal nerve activity was decreased by 44 +/- 5% 41 +/- 4%, 28 +/- 3% and 13 +/- 2% after pontine blockade during infusion of doses 1 to 4, respectively. Similarly, arterial pressure was decreased by 25 +/- 3, 15 +/- 2, 12 +/- 1 and 5 +/- 2 mmHg. Finally, heart rate decreased by 27 +/- 6, 20 +/- 4, 18 +/- 4 and 13 +/- 5 heats per min as the propofol dose increased. The tonic firing of pontine neurons was minimally depressed by the lower two doses of propofol but higher doses did appear to depress their firing, demonstrating dose-dependence of actions of this anaesthetic.(ABSTRACT TRUNCATED AT 250 WORDS)
脑桥神经元的紧张性放电为延髓腹外侧的血管运动中枢提供兴奋性输入。为了加深我们对丙泊酚对控制心血管系统的中枢神经系统神经元作用的理解，我们评估了丙泊酚对脑桥神经元这种紧张性放电的影响。使用8只阿托品化的Wistar大鼠研究了丙泊酚（剂量分别为1 - 4：24±2、40±4、65±3和104±3 mg·kg⁻¹·hr⁻¹）对脑桥神经元的作用。记录肾交感神经的电活动、体动脉血压和心率。丙泊酚在这四个剂量下分别使肾神经活动降低3±2%、23±3%、33±3%和52±4%。动脉压和心率以类似的剂量依赖性方式降低。丙泊酚抑制了通过微量注射甘氨酸阻断脑桥网状结构中的神经元所引起的交感和心血管反应。在输注剂量1至4期间，脑桥阻断后肾神经活动分别降低了44±5%、41±4%、28±3%和13±2%。同样，动脉压分别降低了25±3、15±2、12±1和5±2 mmHg。最后，随着丙泊酚剂量增加，心率分别降低了27±6、20±4、18±4和13±5次/分钟。较低的两个丙泊酚剂量对脑桥神经元的紧张性放电抑制作用最小，但较高剂量似乎确实抑制了它们的放电，表明这种麻醉剂的作用具有剂量依赖性。（摘要截断于250字）
