Korean J Physiol Pharmacol.
2000 Apr;4(2):149-158.
Influence of staurosporine on catecholamine release evoked by
cholinergic stimulation and membrane depolarization from the rat
adrenal gland
- Affiliations
-
- 1Department of Pharmacology, College of Medicine, Chosun University,
Kwangju 501-759, South Korea.
- 2Department of Internal Medicine, Seonam University Hospital, kwangju 501-130, South Korea.
- 3Department of Microbiology, College of Medicine, Chosun University Kwangju 501-759, South Korea.
- 4Department of Anesthesiology, College of Medicine, , Chosun University Kwangju 501-759, South Korea.
Abstract
- The present study was attempted to examine the effect of staurosporine
(STS) on secretion of catecholamines (CA) evoked by cholinergic
stimulation and membrane depolarization from the isolated perfused rat
adrenal gland and to establish its mechanism of action. The perfusion
of STS (3 X 10(-7) ~3 X 10(-8) M) into an adrenal vein for 20 min
produced a dose-dependent inhibition in CA secretion evoked by ACh
(5.32 X 10(-3) M), high K+ (5.6 X 10(-2) M), DMPP (10(-4) M for 2 min),
McN-A-343 (10(-4) M for 2 min), cyclopiazonic acid (10(-5) M for 4 min) and
Bay-K-8644 (10(-5) M for 4 min). Also, in the presence of tamoxifen (2 X
10(-6) M), which is known to be a protein kinase inhibitor, CA secretory
responses evoked by ACh, high K+, DMPP, McN-A-343, Bay-K-8644 and
cyclopiazonic acid were also significantly depressed. However, in
adrenal glands preloaded with STS (10(-7) M) under the presence of
phorbol-12,13-dibutyrate (10(-7) M), a specific activator of protein
kinases (for 20 min), the inhibitory effect of STS on CA secretory
responses evoked by ACh, high K+, DMPP, McN-A-343, Bay-K-8644 and
cyclopiazonic acid was greatly recovered to the extent of the control
release as compared to those in the presence of STS only. These results
demonstrate that STS causes the marked inhibition of CA secretion
evoked by stimulation of cholinergic (both nicotinic and muscarinic)
receptors as well as by membrane depolarization, indicating strongly
that this effect may be mediated by inhibiting influx of extracellular
calcium and release in intracellular calcium in the rat adrenomedullary
chromaffin cells through preventing activation of protein kinases.
Furthermore, these findings also suggest that these STS-sensitive
protein kinases play a modulatory role partly in regulating the rat
adrenomedullary CA secretion.