Sikdar S K, Waring D W, Mason W T
Neurosci Lett. 1986 Oct 30;71(1):95-100. doi: 10.1016/0304-3940(86)90263-6.
Using whole cell recordings of membrane current and voltage from pars tuberalis gonadotrophs, we have examined the basis of membrane excitability in these cells. This technique allows internal perfusion of gonadotrophs, which has permitted the cell to be filled with CsCl solutions, thus removing outward components of K+ current. Under these conditions, tetrodotoxin (TTX)-sensitive Na+ or TTX-insensitive Ca2+ currents on the order of 500 and 100 pA, respectively, could be detected when the membrane potential was depolarised. Na+ currents, however, were at least 50% inactivated at the normal resting membrane potential of the gonadotroph, and required at least 2 s to recover from inactivation. These data provide the first direct observations of voltage-activated ionic currents in pituitary gonadotrophs, and may explain the TTX insensitivity of LH secretion.
利用来自结节部促性腺激素细胞的膜电流和电压的全细胞记录，我们研究了这些细胞中膜兴奋性的基础。这项技术允许对促性腺激素细胞进行内部灌注，从而使细胞充满CsCl溶液，从而去除K+电流的外向成分。在这些条件下，当膜电位去极化时，分别可以检测到约500 pA和100 pA的河豚毒素（TTX）敏感的Na+电流或TTX不敏感的Ca2+电流。然而，在促性腺激素细胞的正常静息膜电位下，Na+电流至少有50%失活，并且从失活状态恢复至少需要2秒。这些数据首次直接观察到垂体促性腺激素细胞中的电压激活离子电流，并可能解释LH分泌对TTX不敏感的原因。
