Single-channel Ba2+ currents in insulin-secreting cells are activated by glyceraldehyde stimulation.
Single-channel Ba2+ current recordings have been made from the insulin-secreting cell line RINm5F with the patch-clamp technique. Depolarization evokes opening of Ca2+ (Ba2+) channels with a relatively high conductance (30 pS) and during the 200 ms depolarizing pulses there is no inactivation. The threshold is high as 50 mV depolarization from the resting membrane potential of -70 mV is required for any channel opening to occur. Glyceraldehyde, a substance evoking insulin secretion from the RINm5F cells, enhances the voltage-activated Ca2+ channel opening by increasing the mean open time and decreasing the longer of the two mean shut times and also decreases the voltage threshold for channel opening.
D000200:Action Potentials; D001464:Barium / Q000378:metabolism*; D002460:Cell Line; D005985:Glyceraldehyde / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007473:Ion Channels / Q000187:drug effects*; D007515:Islets of Langerhans / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D013268:Stimulation, Chemical
D007328:Insulin; D007473:Ion Channels; D001464:Barium; D005985:Glyceraldehyde