Voltage-dependent Ca Current Identified in Freshly Isolated Interstitial Cells of Cajal (ICC) of Guinea-pig Stomach.

The properties of voltage dependent Ca(2+) current (VDCC) were investigated in interstitial cells of Cajal (ICC) distributed in the myenteric layer (ICC-MY) of guinea-pig antrum. In tissue, ICC-MY showed c-Kit positive reactions and produced driving potentials with the amplitude and frequency of about 62 mV and 2 times min(-1), respectively, in the presence of 1 microM nifedipine. Single ICC-MY isolated by enzyme treatment also showed c-Kit immunohistochemical reactivity. These cells were also identified by generation of spontaneous inward current under K(+) -rich pipette solution. The voltage clamp experiments revealed the amplitude of - 329 pA inward current at irregular frequency. With Cs(+)-rich pipette solution at V(h)=-80 mV, ICC-MY produced voltage-dependent inward currents (VDIC), and nifedipine (1 microM) blocked VDIC. Therefore, we successfully isolated c-Kit positive single ICC from guinea-pig stomach, and found that ICC-MY potently produced dihydropiridine sensitive L-type voltage-dependent Ca(2+) currents (VDCC(L)).