Mechanism of enhanced myogenic response in arterioles during sympathetic nerve stimulation.
Mechanism of enhanced myogenic response in arterioles during sympathetic nerve stimulation.
复制标题
交感神经刺激期间小动脉生肌反应增强的机制。
DOI：
10.1152/ajpheart.1992.263.4.h1185
复制
发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Johnson,PC
中科院分区：
文献类型：
--
作者：
Ping,P;Johnson,PC
在以前的研究中，我们发现，在猫缝匠肌的交感神经刺激小动脉肌反应增强。在这项研究中，我们确定是否增强是唯一的交感神经刺激。观察股动脉压从110降到60 mmHg时小动脉内径和红细胞流速的变化。通过去甲肾上腺素输注使直径为40微米的小动脉收缩至与交感神经刺激相似的程度。在去甲肾上腺素输注期间，小动脉扩张至压力降低显著增强，与交感神经刺激期间无显著差异。这表明递质的连接释放不是必需的，并且排除了减压期间神经递质释放的连接前抑制作为增强扩张的重要机制。在加压素或BAY K 8644（一种钙通道激动剂）输注期间，小动脉扩张至压力降低也得到增强。在所有情况下，流量的自动调节显著增强。这些结果表明，肌源性反应的调节发生在平滑肌细胞的受体后位点。
In a previous study we found that the arteriolar myogenic response was enhanced during sympathetic nerve stimulation in the cat sartorius muscle. In this study we determined whether the enhancement was unique to sympathetic nerve stimulation. Changes of arteriolar diameter and red cell velocity during femoral arterial pressure reduction from 110 to 60 mmHg were examined. Arterioles of 40 microns diameter were constricted by norepinephrine infusion to a similar degree as sympathetic nerve stimulation. Arteriolar dilation to pressure reduction was significantly enhanced during norepinephrine infusion and was not significantly different from that during sympathetic nerve stimulation. This indicates that junctional release of transmitters is not essential and rules out prejunctional inhibition of neurotransmitter release during pressure reduction as a significant mechanism in the enhanced dilation. Arteriolar dilation to pressure reduction was also enhanced during vasopressin or BAY K 8644 (a calcium channel agonist) infusion. In all instances, autoregulation of flow was significantly enhanced. These results demonstrate that modulation of the myogenic response occurs at postreceptor sites in the smooth muscle cell.