Abstract
The intrapancreatic neuropeptide galanin has been demonstrated to lower plasma insulin levels in vivo. The effects of this peptide on insulin secretion, cytoplasmic free Ca2+ concentration and membrane potential have now been studied in vitro. Glucose-stimulated insulin secretion was inhibited by galanin under these conditions, indicating a direct effect of the peptide on the β-cells. The neuropeptide reversed both the increase in membrane potential and cytoplasmic free Ca2+ in response to glucose stimulation. At a non-stimulatory concentration of the sugar, galanin induced a slight hyperpolarization without any effect on cytoplasmic free Ca2+. Galanin did not affect K+-induced increase in cytoplasmic free Ca2+, excluding a direct inhibitory effect on the voltage-activated Ca2+ channels. The results indicate that galanin inhibition of glucose-stimulated insulin release involves hyperpolarization with a subsequent decrease in cytoplasmic free Ca2+.
Original language | English (US) |
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Pages (from-to) | 1059-1063 |
Number of pages | 5 |
Journal | Biochemical and biophysical research communications |
Volume | 140 |
Issue number | 3 |
DOIs | |
State | Published - Nov 14 1986 |
ASJC Scopus subject areas
- Biophysics
- Biochemistry
- Molecular Biology
- Cell Biology