Glucagon-like peptide-1 modulates Ca2+ current but not K+ATP current in intact mouse pancreatic B-cells.
The influence of GLP-1 on electrical activity and ion currents of mouse pancreatic B-cells was studied with intracellular microelectrodes and the whole-cell configuration of the patch-clamp technique. In the presence of 15 mmol/l glucose 5, 50 and 100 nmol/l GLP-1 slightly increased electrical activity. This effect may be caused by the slowing of Ca2+ channel inactivation observed with GLP-1. Thus, changes in Ca2+ channel kinetics are suggested to contribute to the insulinotropic action of the hormone. The most prominent effect of GLP-1 on the membrane potential was the conversion of irregular electrical activity into regular oscillations of the membrane potential. At the threshold concentration for insulin secretion (7 mmol/l glucose) GLP-1 did not alter the membrane potential. Accordingly, in patch-clamp experiments GLP-1 had no effect on the whole-cell K+ATP current.
Department of Physiology, University of Tübingen, FRG.
S
S
Britsch
P
P
Krippeit-Drews
F
F
Lang
M
M
Gregor
G
G
Drews
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D005260:Female; D005934:Glucagon / Q000494:pharmacology*; D052216:Glucagon-Like Peptide 1; D004763:Glucagon-Like Peptides; D005947:Glucose / Q000494:pharmacology; D066298:In Vitro Techniques; D007515:Islets of Langerhans / Q000187:drug effects / Q000502:physiology*; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008815:Mice, Inbred Strains; D010446:Peptide Fragments / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D011498:Protein Precursors / Q000494:pharmacology*
D015220:Calcium Channels; D010446:Peptide Fragments; D010455:Peptides; D015221:Potassium Channels; D011498:Protein Precursors; C055453:glucagon-like peptide 1 (7-36)amide; D004763:Glucagon-Like Peptides; D052216:Glucagon-Like Peptide 1; D000255:Adenosine Triphosphate; D005934:Glucagon; D005947:Glucose; C051322:glucagon-like peptide 1 (7-37)