AJP - Endocrinology and Metabolism, Vol 246, Issue 1 38-E43, Copyright © 1984 by American Physiological Society
Mechanism of arginine-stimulated Ca2+ influx into pancreatic B cell
A. Herchuelz, P. Lebrun, A. C. Boschero and W. J. Malaisse
The mechanism by which arginine stimulates Ca2+ inflow into the pancreatic
B cell was investigated. Arginine (10 mM) increased 86Rb outflow from
perifused rat pancreatic islets, suggesting that arginine-stimulated Ca2+
influx into the B cell does not result from a decrease in K+ conductance.
Arginine stimulated Ca2+ uptake in isolated islets over short incubation
periods and increased 45Ca outflow from perifused islets in a
Ca2+-dependent manner. The calcium channel blocker verapamil inhibited both
arginine-stimulated 45Ca uptake and 45Ca outflow. However, the sensitivity
toward verapamil of arginine-stimulated islets was lower than that of
islets stimulated by 20 mM K+, which gates voltage-sensitive Ca2+ channels.
It was similar to that of islets stimulated by 8.3 mM glucose, which is
thought to mainly gate voltage-insensitive Ca2+ channels. It is suggested
that arginine stimulates Ca2+ inflow into the B cell by gating
voltage-insensitive Ca2+ channels. The arginine-induced stimulation of Ca2+
inflow could participate in the depolarizing action of the amino acid on
the B cell membrane.
