NO synthase activity does not influence electrical activity of mouse pancreatic B-cells.
The membrane potential of mouse pancreatic B-cells was recorded with intracellular microelectrodes. At a low concentration the NO synthase inhibitor N omega-nitro-L-arginine methyl ester (L-NAME, 100 mumol/l) did not alter electrical activity induced by 15 mmol/l glucose. At 5 mmol/l L-NAME depolarized B-cells similarly to L-arginine. The depolarization of the B-cell membrane induced by 5 mmol/l L-arginine in the presence of 15 mmol/l glucose was not inhibited but further increased by the addition of 15 mmol/l L-NAME. D-arginine which is not used as a substrate by the NO synthase also depolarized the B-cells. However, higher concentrations were necessary than for L-arginine pointing to a preferential transport of the L-enantiomer. It is concluded that the electrical activity of pancreatic B-cells is not influenced by the NO synthase and that the enzyme is not involved in the arginine-induced depolarization of B-cells.
Drews
G
G
Department of Physiology, University of Tübingen, FRG.
Krippeit-Drews
P
P
D000594:Amino Acid Oxidoreductases / Q000378:metabolism*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D002462:Cell Membrane / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005947:Glucose / Q000494:pharmacology; D066298:In Vitro Techniques; D007515:Islets of Langerhans / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008815:Mice, Inbred Strains; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000037:antagonists & inhibitors; D019001:Nitric Oxide Synthase; D013237:Stereoisomerism
D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D005947:Glucose; D019331:NG-Nitroarginine Methyl Ester