Prolactin, an Activator of Epithelial Na+ Channel, Inhibits Basolateral K+ Channels in Adult Tree Frog Skin
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Accession number;05A0211612
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| Title;Prolactin, an Activator of Epithelial Na+ Channel, Inhibits Basolateral K+ Channels in Adult Tree Frog Skin |
| Author;
TAKADA M
(Saitama Medical School, Saitama, Jpn)
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Journal Title;Zool Sci
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Journal Code:F0012B
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ISSN:0289-0003
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VOL.22;NO.1;PAGE.95-100(2005)
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| Figure&Table&Reference;FIG.5, REF.25 |
| Pub. Country;Japan |
| Language;English |
| Abstract;Adult amphibian skin actively transports Na+ from its apical to basolateral side while in turn, K+ is recycled through Na+, K+-ATPase and K+ channels located in the basolateral membrane. We previously found that PRL stimulates Na+ transport in the skin of the adult tree frog (Hyla arborea japonica) via an increase in the open-channel density of the epithelial Na+ channel (ENaC). If PRL also activates basolateral K+ channels, this activation would help to stimulate Na+ transport, too. Whether PRL does indeed stimulate basolateral K+ channels in the adult tree frog was examined by measuring the short-circuit current across nystatin-treated skin. Both tolbutamide, a KATP channel blocker, and tetrapentylammonium (TPA), a KCa channel blocker, blocked the current, the effect of TPA being more powerful than that of tolbutamide. Contrary to expectation, PRL inhibited the basolateral K+ channels in this skin. In the presence of basolateral amiloride, PRL still inhibited the basolateral K+ current, suggesting that the Na+-H + exchanger located in the basolateral membrane does not mediate the inhibitory effect of PRL on the basolateral K+ channels in Hyla. (author abst.) |
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