Article révisé par les pairs
Résumé : The effect of methylamine on electrical activity and simultaneously measured insulin release was investigated in single perifused islets of normal mice. Methylamine, (2 mmol/L or 6 mmol/L) failed to affect beta-cell input resistance and only caused a modest and transient inhibition of electrical activity of islets exposed to 11.1 mmol/L glucose. Methylamine (2 mmol/L) inhibited insulin release evoked by a five-minute rise in glucose concentration from 5.6 to 22.2 mmol/L, even when the glucose-induced electrical activity remained unaltered. Methylamine, at 2 or 5 mmol/L, partially inhibited insulin release but failed to affect the continuous electrical activity in islets exposed throughout to 22.2 mmol/L glucose. At 10 mmol/L, methylamine reduced both insulin release and electrical activity. These data reinforce the idea that the glucose-induced changes in beta-cell membrane potential represent an early event in the process of stimulus-secretion coupling and can be dissociated from the subsequent process of insulin release.