延髓腹外侧区在猫腹迷走神经加压反应中的作用

Role of Ventrolateral Medulla in Pressor Response Elicited by Stimulation of Abdominal Vagi in Cats

本实验探讨猫延髓腹外侧区在腹迷走神经加压反应中的作用。结果表明,腹外侧区头端是腹迷走神经加压反应的必经之地,参与该加压反应的神经通路在此交换神经元。肾上腺素能α受体和胆碱能M受休亦介于腹迷走神经加压反应通路,而压力感受性反射则不参与腹迷走加压反应的调节。

The experiments were performed on 51 cats of either sex weighing 1.8-2.4 kg to invesligate the role of the ventrolateral medulla in the pressor response elicited by stimulation of central ends of abdominal vagi. We observed that both the stimulation of the central ends of abdominal vagi and occlusion of one carotid artery increased the blood pressure by 17.4 ±1.6mmHg (n=51, P< 0.01) and 14.7±1.9mmHg (n = 19, P<0.0l) respectively;, blockade of the caudal ventrolateral medulla or trapezoid bodies with lidocaine had little effect on blood pressure and the pressor response, but blockade of the rostral ventrolateral medulla with either lidocaine or kainic acid could cause profound depression, and even abolition, of the pressor response. Moreover, application of atropine and phentolamine to the RVL severely inhibited the abdominal vagal pressor response without affecting the baroreceptor reflex. Taken together, we conclude that the RVL is a very important relay in the pathway of the abdominal vagal pressor response in which the adrenergic and cholinergic mechanisms may be involved in the RVL, and it seems that the pressor response pathway is independent of that of the baroreceptor reflex in the RVL.