Patch-clamp recordings were used to study the activation of ion channels in the cell membrane of cultured embryonic chick myotubes treated with the specific activator of protein kinase C, the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA; 1 x 10-7 M). Myotubes exhibited a spontaneous channel activity when the TPA-induced dedifferentiative processes developed. This consisted in the activation of inward current channels (~ 35 pS conductance; ~ 6 ms open time). These spontaneously active channels were insensitive to α-bungarotoxin, curare, atropine and tetrodotoxin and were not inhibited by the withdrawal of TPA. It is suggested that a prolonged stimulation of the protein kinase C causes a irreversible deregulation of the membrane channel function during cell dedifferentiation.
SPONTANEOUS CHANNEL ACTIVITY INDUCED BY TUMOR PROMOTER TPA IN CHICK MYOTUBES / C., Ciccarelli; B. M., Zani; M., Molinaro; Grassi, Francesca; Eusebi, Fabrizio. - In: NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY. - ISSN 0028-1298. - STAMPA. - 338:2(1988), pp. 121-124.
SPONTANEOUS CHANNEL ACTIVITY INDUCED BY TUMOR PROMOTER TPA IN CHICK MYOTUBES
GRASSI, Francesca;EUSEBI, Fabrizio
1988
Abstract
Patch-clamp recordings were used to study the activation of ion channels in the cell membrane of cultured embryonic chick myotubes treated with the specific activator of protein kinase C, the phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA; 1 x 10-7 M). Myotubes exhibited a spontaneous channel activity when the TPA-induced dedifferentiative processes developed. This consisted in the activation of inward current channels (~ 35 pS conductance; ~ 6 ms open time). These spontaneously active channels were insensitive to α-bungarotoxin, curare, atropine and tetrodotoxin and were not inhibited by the withdrawal of TPA. It is suggested that a prolonged stimulation of the protein kinase C causes a irreversible deregulation of the membrane channel function during cell dedifferentiation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.