These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Pharmacological characteristics of receptor-operated and potential-operated Ca2+ channels in rat aorta.
    Author: Chiu AT, McCall DE, Timmermans PB.
    Journal: Eur J Pharmacol; 1986 Aug 07; 127(1-2):1-8. PubMed ID: 2428637.
    Abstract:
    In the rat aorta activation of the potential-operated Ca2+ channels by 100 mM K+ resulted in a greater 45Ca2+ influx than stimulation of the receptor-operated Ca2+ channels by norepinephrine (NE, 3 X 10(-7) M) or angiotensin II (AII, 10(-7) M). 45Ca2+ influx induced by NE was inhibited by prazosin (10(-7) M) but not by yohimbine (10(-6) M) while that by AII was abolished by [Sar1, Ile8]AII (10(-8) M). These receptor antagonists had no effect on the 45Ca2+ influx produced by K+. Bay k 8644 enhanced the influxes to low concentrations of NE and K+ while it was additive with the maximal concentration of NE but not with K+. 3-Isobutyl-1-methyl-xanthine and forskolin inhibited both the influx and efflux of 45Ca2+ elicited by NE but were ineffective against those caused by K+. Nifedipine blocked the efflux of 45Ca2+ induced by K+ but not that evoked by NE. However, both types of Ca2+ channel exhibited the same sensitivity to inhibition by Ca2+ entry blockers (nifedipine/verapamil) on 45Ca2+ influxes. These data suggest that in the rat aorta, the receptor-operated calcium channels and potential-operated calcium channels share similar structural characteristics. However, they are gated separately and distinctly by their respective activators.
    [Abstract] [Full Text] [Related] [New Search]