Regulation of hormone-induced Ca sup 2+ mobilization in the human platelets
- Burroughs Wellcome Co., Research Triangle Park, NC (USA)
{alpha}-Thrombin, {gamma}-thrombin, and platelet-activating factor each stimulated the mobilization of intracellular Ca{sup 2+} stores in aspirin-treated human platelets. This was followed by desensitization of the receptors, as shown by the return of the Ca{sup 2+} level to basal values and by the fact that a subsequent addition of a second different agonist, but not the same agonist, could again elicit a response. Epinephrine, acting on {alpha}{sub 2}-adrenergic receptors, was by itself ineffective at mobilizing Ca{sup 2+} stores. However, when added after the thrombin-induced response, epinephrine could evoke a considerable release of Ca{sup 2+} from cellular stores. This appeared to be due to epinephrine recoupling thrombin receptors to phospholipase C. In support of this, epinephrine was able to induce the formation of inositol triphosphate when added after the response to thrombin had also become desensitized. Alone, epinephrine was without effect. Pre-activation of protein kinase C with the phorbol ester abolished these effects of epinephrine, suggesting that epinephrine was working by activating a protein which could be inactivated by phosphorylation. The current work is to characterize this protein that may be a member of the G{sub i}, GTP-binding protein family.
- OSTI ID:
- 5393803
- Journal Information:
- Environmental Health Perspectives; (United States), Vol. 84; ISSN 0091-6765
- Country of Publication:
- United States
- Language:
- English
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CALCIUM COMPOUNDS
MEMBRANE TRANSPORT
PHORBOL ESTERS
BIOLOGICAL EFFECTS
PHOSPHOTRANSFERASES
ENZYME INDUCTION
ADRENALINE
BLOOD PLATELETS
INOSITOL
MAN
THROMBIN
TRITIUM COMPOUNDS
ADRENAL HORMONES
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BLOOD COAGULATION FACTORS
BODY FLUIDS
CARBOHYDRATES
CARCINOGENS
CARDIOTONICS
CARDIOVASCULAR AGENTS
COAGULANTS
DRUGS
ENZYMES
ESTERS
GENE REGULATION
HEMATOLOGIC AGENTS
HEMOSTATICS
HORMONES
HYDROGEN COMPOUNDS
HYDROLASES
INOSITOLS
MAMMALS
MATERIALS
MONOSACCHARIDES
NEUROREGULATORS
ORGANIC COMPOUNDS
PEPTIDE HYDROLASES
PHOSPHORUS-GROUP TRANSFERASES
PRIMATES
PROTEINS
SACCHARIDES
SERINE PROTEINASES
SYMPATHOMIMETICS
TRANSFERASES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques