to distinguish between these two possibilities , isolated rat pancreatic islets were perifused with agents that raise intracellular levels of camp [ 3-isobutyl-1-methylxanthine ( ibmx ) and forskolin ] and others that increase intracellular concentrations of ca2+ either by blocking na2+-ca2+ exchange ( ouabain and choline-ringer solution ) or by causing increased ca2+ influx ( kcl , carbachol , and 10 mm ca2+ ) .
C0008405
choline
C0006945
carbachol