Using the voltage-clamp technique, a possible role of protein kinase С in regulation of Na+
transport in the skin of the frog Rana temporaria was investigated. It was shown that protein kinase С
activator phorbol ester 12-myristate 13-acetate (PMA), applied to the apical surface of the skin, stimulated
transepithelial Na+ transport, measured as amiloride-sensitive short-circuit current, and also
increased such electrical characteristics of frog skin as the open-circuit potential and transepithelial
conductance. PMA exerts a similar stimulation effect on Na+ transport across the tadpole skin. Specific inhibitors
of protein kinase C, cheleryt-hryne or H-7, almost fully prevented the PMA-induced stimulation of Na+
transport. These data support a concept that the response to PMA was indeed mediated by PKC activation. The results
are compatible with the important role played by protein kinase С in regulation of transepithelial Na+
transport in the skin of R. temporaria.
Key words: frog skin, tadpole skin, Na+ transport, epithelial Na+ channel (ENaC),
amiloride-sensitive short-circuit curent, protein kinase C
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