Fig. 12.
Schematic diagram of the proposed action of caffeine on ICa and intracellular stores and the action of store-released calcium on glutamate release,ICa, and the release-activated calcium transport. Caffeine was shown to suppressICa moderately via a direct action and more significantly via an indirect one in which intracellular calcium led to a decrease in ICa. Caffeine also caused a transient peak in calcium that is attributable to a caffeine-induced release from stores. The depression of [Ca2+]i can be explained by a release-activated uptake into stores and the suppression ofICa.