Han Y M, Chan Y S, Lo K S, Wong T M
Department of Physiology, Faculty of Medicine, The University of Hong Kong, 5 Sassoon Road, Hong Kong, China.
Brain Res. 1998 Dec 7;813(2):262-7. doi: 10.1016/s0006-8993(98)00963-9.
In order to determine the role of the rostral ventrolateral medulla (RVLM) in the development of neurogenic hypertension, the aortic depressor nerves of rats were transected (tADN) to produce neurogenic hypertension. The rate and pattern of firing of the barosensitive RVLM neurons of the treated rats were studied. In neurogenic hypertensive rats, the RVLM barosensitive neurons exhibited a faster firing rate and a shorter interspike interval (ISI) than the corresponding values of the control and sham groups, indicating an enhanced spontaneous activity of these neurons in the hypertensive rats. The coefficient of variation (cv) and skewness (sk) of the ISI histogram, parameters reflecting the regularity of neuronal firing, were smaller in neurogenic hypertensive than in the control and sham-operated rats. Following tADN, the responsiveness of these neurons to blood pressure changes was attenuated, suggesting a reduced intrinsic barosensitivity of neurons and/or a reduced baroreceptor input. The increase in spontaneous activity and firing regularity of RVLM barosensitive neurons imply an enhancement in the efficacy of outflow from these neurons. The increased efficacy of the outflow from the RVLM barosensitive neurons and the resetting of the baroreflex may contribute to the genesis of neurogenic hypertension.
为了确定延髓头端腹外侧区（RVLM）在神经源性高血压发生中的作用，切断大鼠主动脉减压神经（tADN）以诱发神经源性高血压。研究了处理后大鼠中对压力敏感的RVLM神经元的放电频率和模式。在神经源性高血压大鼠中，RVLM压力敏感神经元的放电频率比对照组和假手术组的相应值更快，峰间间隔（ISI）更短，这表明这些神经元在高血压大鼠中的自发活动增强。反映神经元放电规律性的ISI直方图的变异系数（cv）和偏度（sk）在神经源性高血压大鼠中比对照组和假手术组更小。tADN后，这些神经元对血压变化的反应性减弱，提示神经元的内在压力敏感性降低和/或压力感受器传入减少。RVLM压力敏感神经元自发活动和放电规律性的增加意味着这些神经元传出效能增强。RVLM压力敏感神经元传出效能的增加和压力反射的重调定可能有助于神经源性高血压的发生。
