Dibutyryl-cAMP increases basolateral sodium conductance of mosquito Malpighian tubules.
Dibutyryl-cAMP increases basolateral sodium conductance of mosquito Malpighian tubules.
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二丁酰-cAMP 增加蚊子马氏小管的基底外侧钠电导。
DOI：
10.1152/ajpregu.1985.248.3.r339
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Beyenbach,KW
中科院分区：
文献类型：
--
作者：
Sawyer,DB;Beyenbach,KW
二丁酰腺苷3 '，5'-环一磷酸（cAMP）刺激埃及伊蚊离体马氏管的液体分泌。在本研究中，cAMP对基底外侧膜的影响进行了研究与传统的微电极。膜电导从基底外侧膜电位（Vbl）的变化，随之而来的离子在浴中的变化进行了评价。在对照条件下，Vbl测量值为-65.2 +/- 1.5 mV [83个穿刺，67个小管]。钠浴浓度降低5倍使Vbl超极化10.2 +/- 0.6 mV [7]，而钾浴浓度增加4.4倍使Vbl去极化7.9 +/- 1.0 mV [9]。在cAMP（10（-4）M）存在下，Vbl去极化至-24.8 +/- 2.7 mV [9]。Vbl现在对于钠浴变化超极化22.7 +/- 1.5 mV [7]，对于钾浴变化去极化仅3.8 +/- 1.1 mV [6]。因此，cAMP的主要作用是增加基底外侧膜Na电导。这种增加与1）Vbl的去极化和2）跨上皮电压的超极化、跨上皮电阻的降低以及先前观察到的Na和液体分泌的增加一致。自发振荡的VBL观察，不能归因于基底外侧膜钠电导的周期性变化。
Dibutyryladenosine 3',5'-cyclic monophosphate (cAMP) stimulates fluid secretion in isolated Malpighian tubules of the mosquito Aedes aegypti. In the present study the effects of cAMP on the basolateral membrane were studied with conventional microelectrodes. Membrane conductances were evaluated from the changes of the basolateral membrane potential (Vbl) consequent to ion changes in the bath. Under control conditions, Vbl measured -65.2 +/- 1.5 mV [83 impalements, 67 tubules]. A fivefold decrease in the bath Na concentration hyperpolarized Vbl by 10.2 +/- 0.6 mV [7], whereas a 4.4-fold increase in the bath K concentration depolarized Vbl by 7.9 +/- 1.0 mV [9]. In the presence of cAMP (10(-4) M) Vbl depolarized to -24.8 +/- 2.7 mV [9]. Vbl now hyperpolarized by 22.7 +/- 1.5 mV [7] for the bath Na change and depolarized by only 3.8 +/- 1.1 mV [6] for the bath K change. Thus the dominant effect of cAMP is the increase of the basolateral membrane Na conductance. This increase is consistent with 1) the depolarization of Vbl and 2) the hyperpolarization of the transepithelial voltage, the decrease of the transepithelial resistance, and the increase of Na and fluid secretion observed previously. Spontaneous oscillations of Vbl were observed and could not be attributed to cyclical changes of the basolateral membrane Na conductance.