Abstract
The effects of caffeine on Ca 2+ fluxes and catecholamine secretion in bovine adrenal chromaffin cells were examined. Caffeine inhibited secretion, 45Ca 2+ uptake and cytosolic Ca 2+ concentration ([Ca 2+] i) rise induced by the nicotinic receptor agonist 1,1-dimethyl-4-phenylpiperazinium (DMPP) and the Na + channel activator veratridine. The inhibitory effect of caffeine on high K +-induced secretion was smaller than that on DMPP- and veratridine-induced responses. Caffeine only slightly inhibited high K +-induced 45Ca 2+ uptake and did not affect [Ca 2+] i rise. Caffeine also inhibited muscarinic receptor-mediated inositol phosphate generation. Our results suggest that the inhibitory effects of caffeine on bovine chromaffin cells mainly occur at both muscarinic and nicotinic receptors as well as at the voltage-dependent Na + channels and to a smaller extent at site(s) distal to Ca 2+ entry. The effects of caffeine on nicotinic receptors but not on muscarinic receptors can be explained by its ability to raise intracellular cAMP.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: European Journal of Pharmacology: Molecular Pharmacology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
