Possible role of bradykinin on stimulus-secretion coupling in adrenal chromaffin cells.
Nonapeptide bradykinin is known to be a central nervous system neurotransmitter and to play a role in regulation of neuronal function. However, few details are known of the function of its peptide on stimulus-secretion coupling in neuronal cells. In this article, the role of bradykinin on catecholamine biosynthesis, secretion and Ca2+ movement in adrenal chromaffin cells as a model for catecholamine-containing neurons are examined. Bradykinin receptors are classified as B1 and B2 receptor subtypes. These receptors are present on the adrenal chromaffin cell membrane. Bradykinin increases the influx of Ca2+ and the turnover of phosphoinositide through the stimulation of bradykinin B2 receptor. The secretion of catecholamine from the cells is initiated by the raise of [Ca2+]i. An increase in [Ca2+]i and production of diacylglycerol stimulate the activation of calcium-dependent protein kinases. These kinases stimulate the activation of tyrosine hydroxylase, a rate-limiting enzyme in the biosynthesis of catecholamine. Otherwise, bradykinin increases Ca2+ efflux from the cells through the stimulation of the bradykinin-B2 receptor. This action may be explained by an extracellular Na(+)-dependent mechanism, probably through acceleration of Na+/Ca2+ exchange. It is interesting that bradykinin, which stimulates the biosynthesis and secretion of catecholamine in adrenal chromaffin cells, plays a role in the termination of calcium-signal transduction through the stimulation of Ca2+ efflux from the cells.
Division of Pharmacy, University Hospital, Tokushima, Japan.
H
H
Houchi
M
M
Azuma
M
M
Yoshizumi
T
T
Tamaki
K
K
Minakuchi
D000311:Adrenal Glands / Q000502:physiology*; D000818:Animals; D001920:Bradykinin / Q000502:physiology*; D002118:Calcium / Q000502:physiology; D002395:Catecholamines / Q000502:physiology*; D019439:Chromaffin Cells / Q000502:physiology*; D006801:Humans
D002395:Catecholamines; D001920:Bradykinin; D002118:Calcium