Transient extracellular volume reduction in neural lobe of rat hypophysis in response to neural stalk stimulation in vitro and its relationship to extracellular potassium.
Transient extracellular volume reduction in neural lobe of rat hypophysis in response to neural stalk stimulation in vitro and its relationship to extracellular potassium.
复制标题
大鼠垂体神经叶响应体外神经柄刺激的瞬时细胞外体积减少及其与细胞外钾的关系。
DOI：
10.1152/jn.1993.69.4.1363
复制
发表时间：
1993
影响因子：
2.5
通讯作者：
Rice,ME
中科院分区：
文献类型：
--
作者：
Armstrong,WE;Rice,ME
1.使用离子敏感微电极，在神经叶细胞外空间的局部体积的瞬时减少被发现伴随着由刺激神经柄引起的细胞外钾的升高。当刺激频率为1 ~ 40 Hz时，血容量减少和钾离子增加的刺激-反应曲线相似，最大反应出现在20 Hz。刺激持续时间的曲线发散，因为在4-16秒内用20-Hz刺激达到接近最大的钾反应，而细胞外容积减少在64秒时最大。2.体积的减少，但不是钾的增加，强烈抑制降低浴温度和适度抑制呋塞米和降低细胞外氯离子浓度。哇巴因可增强容量反应和钾反应。3.总之，神经活动期间神经叶局部细胞外间隙的收缩是由代谢活性过程介导的，该过程仅部分依赖于细胞外氯化物浓度和阴离子-阳离子共转运，但相对独立于Na（+）-K+泵活性。在神经垂体神经活动增加期间细胞外空间的短暂收缩预计将在激素扩散、离子缓冲和细胞外电流流动中发挥作用。
1. Using ion-sensitive microelectrodes, a transient reduction in the local volume of neural lobe extracellular space was found to accompany the elevation in extracellular potassium induced by stimulation of the neural stalk. The volume decrease and potassium increase had similar stimulus-response curves when stimulus frequency was varied from 1 to 40 Hz, with maximal response at 20 Hz. The curves for stimulus duration diverged, as a near maximal potassium response was reached in 4-16 s with a 20-Hz stimulus, while the extracellular volume decrease was maximal at 64 s. 2. The volume decrease, but not the potassium increase, was strongly inhibited by lowering bath temperature and moderately inhibited by furosemide and by lowering extracellular chloride concentration. Both the volume and the potassium response were enhanced by ouabain. 3. In conclusion, shrinkage of the local extracellular space in neural lobe during nerve activity is mediated by a metabolically active process which is only partially dependent upon extracellular chloride concentration and anion-cation co-transport, but is relatively independent of Na(+)-K+ pump activity. A transient shrinkage in extracellular space during increased neurohypophysial nerve activity would be expected to play a role in hormone diffusion, ion buffering, and extracellular current flow.