[Ion channels in rat pancreatic beta cells].
Using perforated and cell-attached patch clamp techniques, the characteristics of ATP sensitive K(+) channels (K(ATP)), delayed rectifier K(+) channels (K(DR)), Ca(2+) and Na+ channels on single rat pancreatic beta cell membranes were studied. The results showed that (1) the efflux and influx conductance of K(ATP) channels was about 31 and 65 pS respectively, and the reversal potential of K(ATP) was about   60 mV; (2) K(DR) was activated completely after a latency of 20 ms, and K(DR) was about 1/3 of K(ATP); (3) whole cell Ca(2+) current reached a peak (40  60 pA) at 0 mV; L-type Ca(2+) channel was the main Ca(2+) channel in beta cells, but other types of high voltage activated Ca(2+) channels existed as well; and   4) whole cell Na(+) current reached a peak (200  400 pA) at 10 mV; but the expression level of Na(+) channel in beta cells varied among the cells. About half of the beta cells virtually had no Na(+) currents.
Zeng
X H
XH
Institute of Biophysics and Biochemistry, Huazhong University of Science and Technology, Wuhan 430074, China.
Lou
X L
XL
Qu
A L
AL
Wu
H X
HX
Zhou
Z
Z
D000818:Animals; D015220:Calcium Channels / Q000378:metabolism*; D002478:Cells, Cultured; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000378:metabolism*; D051381:Rats; D015222:Sodium Channels / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D015220:Calcium Channels; D015221:Potassium Channels; D015222:Sodium Channels; D000254:Sodium-Potassium-Exchanging ATPase