Moreover, partial inhibition of a-cell K_SlOW with apamin depolarized membrane potential (Vm) (3.8 ± 0.7 mV) and reduced action potential (AP) amplitude (10.4 ± 1.9 mV). Although apamin transiently increased Ca~(2+) influx into a-cells at low glucose (42.9 ± 10.6%), sustained SK (38.5 ± 10.4%) or BK channel inhibition (31.0 ± 11.7%) decreased a-cell Ca~(2+) influx. Total a-cell Ca~(2+)_C was similarly reduced (28.3 ± 11.1%) following prolonged treatment with high glucose, but it was not decreased further by SK or BK channel inhibition. Consistent with reduced a-cell Ca~(2+)_C following prolonged K_SlOW inhibition, apamin decreased GCG secretion from mouse (20.4 ± 4.2%) and human (27.7 ± 13.1%) islets at low glucose.
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