Ardizzone C, Lippe C
Boll Soc Ital Biol Sper. 1983 Jun 30;59(6):844-9.
An SH reactive agent, N-ethylmaleimide (NEM), if introduced in the serosal bath (10(-4) M), stimulates the short circuit current (SCC) across the frog skin. This effect is due to an increase of Na active transport, because is inhibited by ouabain (10(-4) M). A stimulatory action on Cl- or HCO3- secretion can be ruled out because the rise in SCC occurs also in the absence of Cl- or HCO3-. It is known that NEM inhibits the ADH action by forming covalent bounds with SH groups of ADH membrane receptors (1). Thus it is possible that this binding should mimic the ADH action on SCC. In order to test this hypothesis, we studied the effect of serosal NEM on SCC both in the absence and in the presence of I midazol (20 mM), an activator of the cyclic AMP phosphodiesterase. Imidazol treatment decreases the effect of NEM on SCC. Thus we conclude that NEM serosal treatment is able to mimic some ADH effects, by using the same ways of the ormone action.
一种具有SH反应活性的试剂，N-乙基马来酰亚胺（NEM），如果加入到浆膜浴中（10⁻⁴ M），会刺激蛙皮的短路电流（SCC）。这种效应是由于钠主动转运增加所致，因为它会被哇巴因（10⁻⁴ M）抑制。可以排除对氯离子或碳酸氢根离子分泌的刺激作用，因为在没有氯离子或碳酸氢根离子的情况下，短路电流也会升高。已知NEM通过与抗利尿激素膜受体的SH基团形成共价键来抑制抗利尿激素的作用（1）。因此，这种结合有可能模拟抗利尿激素对短路电流的作用。为了验证这一假设，我们研究了在不存在和存在环磷酸腺苷磷酸二酯酶激活剂咪唑（20 mM）的情况下，浆膜NEM对短路电流的影响。咪唑处理降低了NEM对短路电流的影响。因此我们得出结论，浆膜NEM处理能够通过与激素相同的作用方式模拟一些抗利尿激素的作用。
