Adrenaline stimulates glucagon secretion in pancreatic A-cells by increasing the Ca2+ current and the number of granules close to the L-type Ca2+ channels.
1997 (English)In: The Journal of General Physiology, ISSN 0022-1295, Vol. 110, no 3, 217-28 p.Article in journal (Refereed) Published
We have monitored electrical activity, voltage-gated Ca2+ currents, and exocytosis in single rat glucagon-secreting pancreatic A-cells. The A-cells were electrically excitable and generated spontaneous Na+- and Ca2+-dependent action potentials. Under basal conditions, exocytosis was tightly linked to Ca2+ influx through omega-conotoxin-GVIA-sensitive (N-type) Ca2+ channels. Stimulation of the A-cells with adrenaline (via beta-adrenergic receptors) or forskolin produced a greater than fourfold PKA-dependent potentiation of depolarization-evoked exocytosis. This enhancement of exocytosis was due to a 50% enhancement of Ca2+ influx through L-type Ca2+ channels, an effect that accounted for <30% of the total stimulatory action. The remaining 70% of the stimulation was attributable to an acceleration of granule mobilization resulting in a fivefold increase in the number of readily releasable granules near the L-type Ca2+ channels.
Place, publisher, year, edition, pages
1997. Vol. 110, no 3, 217-28 p.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-161886PubMedID: 9276750OAI: oai:DiVA.org:uu-161886DiVA: diva2:457772