THE ROLE OF PROTEIN KINASE Ñ IN Na+ TRANSPORT REGULATION IN THE SKIN OF
ADULT FROGS AND TADPOLES OF RANA TEMPORARIA
Z. I. Krutetskaya, O. E. Lebedev, A. V. Pashina
Chair of Biophysics, St. Petersburg State University
Using the voltage-clamp technique, a possible role of protein kinase Ñ in regulation of Na+
transport in the skin of the frog Rana temporaria was investigated. It was shown that protein kinase Ñ
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 Ñ 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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