Demonstration of the existence of receptor-dependent calcium channels in the platelets
Recently, with the new methodology of measuring calcium ion concentration in the cytoplasm with the aid of the fluorescent indicator, it has been shown that calcium is a second messenger, mediating the action of many hormones, neuromediators, and other extracellular factors. Another argument in support of the existence of receptor-dependent calcium channels is provided by data on the activation by agonists of the uptake of /sup 45/Ca by the cells. In all the studies cited, the conditions were such that the passage of Ca/sup 2 +/ through the potential-dependent channels was excluded. In this paper, evidence is presented for the existence of receptor-dependent calcium channels in the plasma membrane using human platelets as the objects. Two approaches were used. First, the authors determined the binding of /sup 45/Ca by the platelets. In this case, to determine whether /sup 45/Ca passes into the cytoplasm or is adsorbed on the membrane, the authors compared its uptake by simply washed platelets and by platelets in whose cytoplasm buffer capacity for calcium was artificially created with quin 2. The second approach was based on the data of Hallam and Rink, who showed that agonists that increase the calcium level in the platelets induce an intake of Mn/sup 2 +/ ions into the cell in a calcium-free medium.
- Research Organization:
- All-Union Cardiologic Science Center, Moscow, USSR
- OSTI ID:
- 5856421
- Journal Information:
- Dokl. Biochem. (Engl. Transl.); (United States), Vol. 289:1-6; Other Information: Translated from Dokl. Akad. Nauk SSSR; 289: No.1, 220-224(Jul 1986)
- Country of Publication:
- United States
- Language:
- English
Similar Records
Platelet activating factors alters calcium homeostasis in cultured vascular endothelial cells
Amino acid receptors mediate calcium permeability in synaptosomes from rat brain
Related Subjects
BLOOD PLATELETS
CELL MEMBRANES
CYTOPLASM
RADIORECEPTOR ASSAY
CALCIUM 45
RADIONUCLIDE KINETICS
CALCIUM COMPOUNDS
MEMBRANE TRANSPORT
METABOLISM
RECEPTORS
BINDING ENERGY
BIOLOGICAL PATHWAYS
CYTOCHEMISTRY
MAN
UPTAKE
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMISTRY
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CALCIUM ISOTOPES
CELL CONSTITUENTS
CHEMISTRY
DAYS LIVING RADIOISOTOPES
ENERGY
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
MATERIALS
MEMBRANE PROTEINS
MEMBRANES
NUCLEI
ORGANIC COMPOUNDS
PRIMATES
PROTEINS
RADIOISOTOPES
TRACER TECHNIQUES
VERTEBRATES
550301* - Cytology- Tracer Techniques
550501 - Metabolism- Tracer Techniques