Thompson I G, Mills J W
Am J Physiol. 1981 Nov;241(5):C250-7. doi: 10.1152/ajpcell.1981.241.5.C250.
In this study we report on isoproterenol-induced changes in short-circuit current (SCC) that are located in the glands of the frog skin. Following complete inhibition of the SCC with amiloride (10(-4) M), the addition of isoproterenol (9.0 X 10(-7) M) to the serosal side of the skin elicits a significant increase in SCC from 0.6 +/- 0.1 to 3.9 +/- 0.5 microA/cm2 (p less than 0.001). The conductance is doubled, and both effects are blocked completely with the beta-blocking agent propranolol. In the split-skin preparation, in which no glands are present, there is no current response to isoproterenol following amiloride. This indicates that the amiloride-insensitive isoproterenol-stimulated SCC resides in the glands. In the intact skin, removal of sodium (choline replacement) from the serosal (but not the mucosal) medium abolishes this current change. The postisoproterenol current change in amiloride-inhibited skins is also dependent on the presence of chloride in the serosal bath. Preincubation of the amiloride-inhibited skin with ouabain (10(-4) M) for 10 min prior to the addition of isoproterenol reduces the isoproterenol response by 50%. These results indicate that there is a sodium- and chloride-dependent ouabain-sensitive secretory mechanism in the skin glands of the frog that is responsible for the development of the isoproterenol-stimulated SCC observed in the presence of amiloride.
在本研究中，我们报告了异丙肾上腺素引起的青蛙皮肤腺体短路电流（SCC）的变化。用氨氯吡咪（10⁻⁴M）完全抑制SCC后，在皮肤浆膜侧加入异丙肾上腺素（9.0×10⁻⁷M），可使SCC从0.6±0.1显著增加至3.9±0.5微安/平方厘米（p＜0.001）。电导增加一倍，两种效应均被β受体阻滞剂普萘洛尔完全阻断。在无腺体的皮肤分离制备中，氨氯吡咪处理后对异丙肾上腺素无电流反应。这表明氨氯吡咪不敏感的异丙肾上腺素刺激的SCC存在于腺体中。在完整皮肤中，从浆膜（而非粘膜）培养基中去除钠（用胆碱替代）可消除这种电流变化。氨氯吡咪抑制的皮肤中异丙肾上腺素作用后的电流变化也依赖于浆膜浴中氯离子的存在。在加入异丙肾上腺素之前，将氨氯吡咪抑制的皮肤与哇巴因（10⁻⁴M）预孵育10分钟，可使异丙肾上腺素反应降低50%。这些结果表明，青蛙皮肤腺体中存在一种钠和氯依赖性的哇巴因敏感分泌机制，该机制导致在氨氯吡咪存在下观察到的异丙肾上腺素刺激的SCC的产生。
