The intrapancreatic neuropeptide galanin potently inhibits glucose-induced insulin secretion. This effect is in part due to a repolarization of the β-cells and ensuring reduction in the cytoplasmic free Ca2+ concentration, [Ca2+]i. We propose that galanin inhibition of β-cell action potentials is associated with the appearance of ATP-regulated K+ channels. Galanin opens K+ channels in a patch membrane when applied to the external solution in the cell-attached patch configuration. However, galanin does not detectably increase K+ permeability during whole-cell experiments, even when GTP was included in the internal solution. Our findings are not consistent with a direct effect of galanin on the K+ channels, but rather indicate that the effect of the neuropeptide is mediated by some intracellular coupling factor(s).
- Insulin secretion
- K channels
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience