Cation exchange-a common mechanism in the storage and release of biogenic amines stored in granules (vesicles)?

Abstract

The matrices of the amine storing granules in [rat] mast cells, chromaffin cells and noradrenergic nerves show properties reminiscent of cation exchanger materials. In vitro, the amines are released from their granule storage sites on exposure of the granules to cations, e.g., Na+. The propoasl is made that also in vivo the release of transmitter amines is the result of cation exchange amine+ .dblarw. Na+ ions and that the release of transmitter amines occurs as a nonexocytotic fractional release engaging mutliple granules instead of exocytotic emptying of a few. Some physiological and pharamcological implications of a fractional transmitter release are discussed.