Voltage-dependent Ca<SUP>2＋</SUP> Current Identified in Freshly Isolated Interstitial Cells of Cajal (ICC) of Guinea-pig Stomach

Voltage-dependent Ca<SUP>2＋</SUP> 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<i>-Kit</i> positive reactions and produced driving potentials with the amplitude and frequency of about 62 mV and 2 times min^&#8722;1, respectively, in the presence of 1&lt;/SUP&gt;&#1356;M nifedipine. Single ICC-MY isolated by enzyme treatment also showed c<i>-Kit</i> 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 <i>V</i>_h=&#8722;80 mV, ICC-MY produced voltage-dependent inward currents (VDIC), and nifedipine (1&#1356;M) blocked VDIC. Therefore, we successfully isolated c<i>-Kit</i> 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).