BAY K 8644-induced enhancement of 45Ca uptake by rabbit aortic rings
BAY K 8644, a Ca/sup 2 +/ channel activator, enhances uptake of /sup 45/Ca by rabbit aortic rings. This effect depends on the concentration of K/sup +/ in the medium: at 20 mM K/sup +/ the effect of BAY K 8644 was more pronounced than at 5 mM, whereas at 80 mM, no significant enhancement of /sup 45/Ca uptake by BAY K 8644 was found. In the medium containing 5 mM K/sup +/, BAY K 8644 was effective in experiments involving 10 or 30 (but not 3) min exposure of aortic rings to /sup 45/Ca. The dose-response curve for BAY K 8644 was established in 5 mM K/sup +/-containing medium and for 30 min exposure to /sup 45/Ca. BAY K 8644 was effective at 0.01 microM and higher concentrations. In the presence of norepinephrine (0.1 or 10 microM), BAY K 8644 had no greater effect on /sup 45/Ca uptake than in control 5 mM K/sup +/ medium. Our observation that the presence of norepinephrine in 5 mM K/sup +/ did not enhance BAY K 8644-induced /sup 45/Ca uptake suggests that activation of alpha-adrenergic receptor does not depolarize aortic membranes to the same extent as an increase in K+ concentration to 20 mM or that BAY K 8644 does not enhance Ca/sup 2 +/ entry through receptor-operated channels.
- Research Organization:
- Miles Institute for Preclinical Pharmacology, New Haven, CT
- OSTI ID:
- 5003645
- Journal Information:
- J. Cardiovasc. Pharmacol.; (United States), Vol. 4
- Country of Publication:
- United States
- Language:
- English
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AORTA
RADIONUCLIDE KINETICS
CALCIUM 45
UPTAKE
ADRENALINE
DOSE-RESPONSE RELATIONSHIPS
IN VITRO
RABBITS
VASOCONSTRICTION
ADRENAL HORMONES
ALKALINE EARTH ISOTOPES
ANIMALS
ARTERIES
AUTONOMIC NERVOUS SYSTEM AGENTS
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BETA-MINUS DECAY RADIOISOTOPES
BLOOD VESSELS
BODY
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CARDIOVASCULAR AGENTS
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DRUGS
EVEN-ODD NUCLEI
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INTERMEDIATE MASS NUCLEI
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MAMMALS
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NUCLEI
ORGANS
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STEROID HORMONES
SYMPATHOMIMETICS
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560172* - Radiation Effects- Nuclide Kinetics & Toxicology- Animals- (-1987)