Differential blockade of agonist- and depolarization-induced sup 45 Ca2+ influx in smooth muscle cells

Journal Article · Sun Oct 01 00:00:00 EDT 1989 · American Journal of Physiology; (USA)

OSTI ID:5161392

Wallnoefer, A C; Cauvin, C; Lategan, T W; Rueegg, U T ^[1]

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1. Preclinical Research, Sandoz Limited, Basel (Switzerland)

ATP stimulated {sup 45}Ca2+ influx in rat aortic smooth muscle cells in a concentration-dependent manner (EC50 = 3.6 +/- 0.5 X 10(-7) M). ADP and GTP were less effective than ATP in stimulating {sup 45}Ca2+ influx; AMP was weakly active and the adenosine agonist 5'-(N-ethyl-carboxamido)-adenosine (NECA) had no effect. ATP gamma S was about equieffective with ATP, whereas alpha,beta-methylene-ATP (APCPP) did not induce {sup 45}Ca2+ influx. Stimulation of {sup 45}Ca2+ influx by ATP was not abolished by the dihydropyridine Ca2+ channel antagonist darodipine (PY 108-068), which completely blocked depolarization-induced {sup 45}Ca2+ influx. Inorganic cations (La3+, Cd2+, Co2+, Ni2+, Mn2+, and Mg2+) were able to inhibit both agonist- and depolarization-induced {sup 45}Ca2+ influx. Cd2+, however, was approximately 20 times more selective in blocking K+-stimulated than agonist-stimulated {sup 45}Ca2+ influx. These data indicate that ATP-stimulated Ca2+ influx in rat aortic smooth muscle cells is resistant to darodipine but is reduced by La3+, Cd2+, and other inorganic blockers of Ca2+ channels.

• OSTI ID: 5161392
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 257; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALI METAL COMPOUNDS
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
ANIMALS
AORTA
ARTERIES
ATP
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BLOOD VESSELS
BODY
CALCIUM
CALCIUM 45
CALCIUM ISOTOPES
CARDIOVASCULAR SYSTEM
CATIONS
CELL CONSTITUENTS
CELL MEMBRANES
CHARGED PARTICLES
DAYS LIVING RADIOISOTOPES
DOSE-RESPONSE RELATIONSHIPS
ELEMENTS
ENZYME INHIBITORS
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
IONS
ISOTOPE APPLICATIONS
ISOTOPE DILUTION
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
MEMBRANE TRANSPORT
MEMBRANES
METALS
MUSCLES
NUCLEI
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANS
PORINS
POTASSIUM COMPOUNDS
PROTEINS
RADIOISOTOPES
RATS
REACTION KINETICS
RODENTS
TRACER TECHNIQUES
VERTEBRATES