Increasing gracilis muscle interstitial potassium concentrations stimulate group III and IV afferents.
Increasing gracilis muscle interstitial potassium concentrations stimulate group III and IV afferents.
复制标题
股薄肌间质钾浓度的增加会刺激第 III 组和第 IV 组传入神经。
DOI：
10.1152/jappl.1985.58.3.936
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Kaufman,MP
中科院分区：
文献类型：
--
作者：
Rybicki,KJ;Waldrop,TG;Kaufman,MP
静态肌肉收缩反射性地增加动脉血压和心率。引起这种反射的一种可能机制是钾在工作肌肉的间隙中积聚以刺激III和IV组传入神经，其激活反过来引起升压反应。组III和IV肌肉传入的反应，增加间质钾浓度的范围内引起的静态收缩是未知的。因此，我们将氯化钾注入麻醉犬的股薄肌动脉，同时用钾选择性电极测量股薄肌间质钾浓度和股薄肌神经传入冲动活动。我们发现，增加间质钾浓度的水平类似于静态收缩刺激14组16和29组31 IV传入。传入神经对钾离子的反应呈浓度依赖性。对钾的典型反应包括脉冲的爆发，这种效应在26秒内恢复到控制放电率，即使间质钾浓度在几分钟内保持升高。虽然我们的研究结果表明，钾离子可能在启动静态肌肉收缩的反射性心血管反应中发挥作用，但这种离子的积累似乎并不是维持收缩期间升压反应的唯一原因。
Static muscular contraction reflexly increases arterial blood pressure and heart rate. One possible mechanism evoking this reflex is that potassium accumulates in the interstitial space of a working muscle to stimulate group III and IV afferents whose activation in turn evokes a pressor response. The responses of group III and IV muscle afferents to increases in interstitial potassium concentrations within the range evoked by static contraction are unknown. Thus we injected potassium chloride into the gracilis artery of anesthetized dogs while we measured both gracilis muscle interstitial potassium concentrations with potassium-selective electrodes and the impulse activity of afferents in the gracilis nerve. We found that increasing interstitial potassium concentrations to levels similar to those seen during static contraction stimulated 14 of 16 group III and 29 of 31 group IV afferents. The responses of the afferents to potassium were concentration dependent. The typical response to potassium consisted of a burst of impulses, an effect that returned to control firing rates within 26 s, even though interstitial potassium concentrations remained elevated for several minutes. Although our results suggest that potassium may play a role in initiating the reflex cardiovascular responses to static muscular contraction, the accumulation of this ion does not appear to be solely responsible for maintaining the pressor response for the duration of the contraction.