麻醉对去大脑大鼠颈总动脉注射辣椒素产生的呼吸和心血管活动的影响

Anesthesia alters the cardiorespiratory activities elicited by intracarotid injection of capsaicin in the decerebrate rats

目的观察戊巴比妥钠麻醉对颈内动脉注射辣椒素引发的呼吸和心血管反应的影响。方法24只SD大鼠随机分成麻醉和无麻醉两组,在去大脑前给予戊巴比妥钠,分别在去大脑后20min和4h经颈总动脉注射CAP,并监测潮气量(VT)、呼吸频率(f)、分钟通气量(VE)、呼气时间(TE)、平均动脉压(MABP)、心率(HR)的变化。结果注射CAP后,两组大鼠均产生了呼气时间的延长即呼吸暂停,麻醉组大鼠的呼气时间延长几乎是无麻醉组的1倍(P<0.05),VE也低于无麻醉大鼠;CAP使两组动物的MABP均升高,组间比较差异无统计学意义;去大脑增加大鼠的VT,从而使VE增加。结论颈总动脉注射辣椒素引发的呼吸暂停不依赖麻醉,但能被麻醉强化。

Objective The goal of this study is to determine the effects of pentobarbital anesthesia on the CAP-induced cardiorespiratory activities. Methods 24 rats with decerebration were assigned into an anesthetized and an unanesthetized group. 20min and 4h after decerebration, intrscarotid injection of CAP were performed in the anesthetized and unanesthetized groups of rats. Tidal I volume（VT ）, respiratory frequency （f）, minute ventilation （ VE ）, expiratory time （TE）, Mean arterial blood pressure （ MABP ）, and heart rat （HR）were analyzed. Results Our results showed that ：①intracarotid injection of CAP produced an apnea and elevated MABP （ P 〈 0.05） in. both the anesthetized and unanesthetized rats; ②as compared to the unanesthotized, the apneic duration observed in the anesthetized mrs was approximately doubled（ P 〈 0.05） ;③decerebration alone increased baseline VT resulting in an increase in VE（ P 〈 0.05） With little effect on cardiovascular activity（P 〉 0.05）. Conclusion These results demonstrated that the apnea induced by intracarotid injection of CAP is independent of, but strengthened by anesthesia.