The goal of this study was to determine the origin and transmission pathway of respiratory drive to hypoglossal motoneurons. First we recorded intracellularly from 28 antidromically activated inspiratory hypoglossal motoneurons (resting membrane potential, -50

目的　研究嘌呤能受体(purinergic receptors,P2) 家族中P2X 不同亚型在新生和成年SD大鼠延髓的表达。方法　成年SD大鼠(6-8w) 和新生SD大鼠(1-5d)，各6只,雌雄不计，取延髓。应用免疫组织化学的方法和图像分析技术，比较P2X2和P2X4受体在新生和成年SD大鼠延髓的表达。结果　P2X2和P2X4嘌呤受体的阳性神经元和阳性纤维在新生鼠和成年鼠的延髓都有广泛表达，主要分布在孤束核、Ⅻ颅神经核和延髓腹外侧区，延髓其他区域为散在的分布。成年鼠和新生鼠的P2X2受体均比P2X4受体表达水平高。在新生鼠髓,P2X2 和P2X4的表达水平均比成年鼠低。结论　P2X2 和P2X4阳性神经元和阳性纤维广泛分布在大鼠延髓,为ATP对心血管活动、呼吸活动和痛觉等的调节作用提供了结合位点,也有利于实验中P2X受体亚型阻断剂的选择。随着动物发育成熟,P2X2和P2X4表达水平均增加。

Expiratory neurones, with a decrementing firing pattern during the first phase of expiration (EDEC) and located in the rostral ventrolateral medulla, are thought to be involved in the network generating respiratory rhythm, which also includes expiratory neurones with augmenting firing patterns (E-AUG). We used crosscorrelation to detect their synaptic interconnections and connections to phrenic motoneurones in 32 vagotomised, decerebrate, paralysed and ventilated male rats. Pairs of neurones were recorded extracellularly with glass-insulated tungsten microelectrodes and the whole phrenic nerve with bipolar silver wire electrodes. Of the 79 crosscorrelograms computed between pairs of E-DEC neurones, 8 (-10%) showed evidence for inhibitory connections. Of the 67 cross-correlograms computed between EDEC and E-AUG neurones, 5 (7.5%) showed evidence for a monosynaptic inhibition of the E-AUG neurone by the E-DEC neurone, while 3 (4.5%) showed evidence for a monosynaptic inhibition of the E-DEC neurone by the EAUG neurone. An inhibitory connection from E-DEC neurones to phrenic motoneurones was detected in 5 (-2%) of the cross-correlograms, and from E-AUG neurones to phrenic motoneurones in 4 (-3.7%). These results are the first demonstration that network models of rhythm generation in the rat involving reciprocal inhibition between E-DEC and E-AUG neurones could have a neurophysiological basis, and the first to demonstrate that phrenic motoneurones are inhibited during the early phase of expiration by E-DEC neurones.

This study was to observe the changes of the neuronal and inducible nitric oxidesynthase(nNOS ＆ iNOS) as well as their mRNAs in the rostral ventrolateral mudulla(RVLM) of stress-induced hypertensive rats before and after acupuncture, and thereby to infer the curative mechanism of acupuncture on hypertension. The result indicated that the systolic blood pressure(SBP) of stress group rats was increased significantly(P＜0.01), it was accompanied that the expression of nNOS in the RVLM, including the immunoreactive neuron number(P＜0.05), the optical density(OD)(P＜0.01), and the mRNA(P＜0.01) were obviously elevated, while those of iNOS(P＜0.05, P＜0.01 and P＜0.01) were evidently lowered in the stress-induced hypertensive rats. Electroacupuncture(EA) points at "Zusanli" (St.36) and "Lanwei"(Extra 37) on the same hindlimb were stimulated by an EA apparatus(Type G6805-2) with dense sparse wave(4-20Hz) and 4mA intensity. EA application could return the SBP(P＜0.05), and the changes on the expression of both nNOS and iNOS(P＜0.05, P＜0.01 and P＜0.01). These results suggest that the curative mechanism of acupuncture on stress-induced hypertension is related to the changes of nNOS and iNOS in the RVLM of rats