辣椒素对大鼠延髓腹外侧头端区神经元电活动的影响

在35只切断两侧缓冲神经的麻醉大鼠,应用细胞外记录的电生理学方法,观察颈总动脉注射辣椒素(capsaicin)对延髓腹外侧头端区(RVLM)巨细胞旁外侧核(PGL)自发电活动的影响。所得结果如下:(1)颈动脉注射辣椒素(10μmol,01ml),MAP由1074±013升至1256±021kPa(P<0001);HR由374±4增至395±5bpm(P<0001);30个PGL神经元自发放电单位的放电频率由126±07增至209±11spikes/s(P<0001)。(2)在10个放电单位,应用辣椒素受体阻断剂钌红(rutheniumred;200mmol,01ml)后,明显抑制辣椒素的上述效应。以上结果提示,辣椒素可能通过激活RVLM神经元上的辣椒素受体,进而兴奋PGL神经元

Effects of intracarotid injection of capsaicin on electrical activity of rostral ventrolateral medullary neurons in rats

The effects of intracarotid injection of capsaicin on spontaneous electrical activity of nucleus paragigantocellularis lateralis (PGL) neurons in rostral ventrolateral medulla (RVLM) were examined in 35 anesthetized rats with sino-aortic denervation by using extracellular recording technique. The results obtained were as follows: (1) In response to intracarotid injection of capsaicin (10 mumol, 0.1 ml), MAP was increased from 10.74 +/- 0.13 to 12.56 +/- 0.21 kPa (P < 0.001), and HR from 374 +/- 4 to 395 +/- 5 bpm (P < 0.001). All of 30 PGL neurons recorded responded to intracarotid injection of capsaicin with an increase in spontaneous discharge rate from 12.6 +/- 0.7 to 20.9 +/- 1.1 spikes/s (P < 0.001); (2) In 10 units, the excitatory response of PGL neurons to intracarotid injection of capsaicin was significantly inhibited by pretreatment with the vanilloid receptor (capsaicin receptor) antagonist ruthenium red (200 mmol, 0.1 ml). These results suggest that capsaicin may stimulate the vanilloid receptor of neurons in RVLM, thereby resulting in activation of PGL neurons.