Alpha 2-adrenoceptor coupling to adenylate cyclase in adrenaline insensitive human platelets. 1985

S S Swart, and M Maguire, and J K Wood, and D B Barnett

Coupling of the alpha 2-adrenoceptor to adenylate cyclase was assessed in platelets from 3 groups of subjects: normal controls and patients with myeloproliferative disorders whose platelets were either sensitive or specifically insensitive to the aggregatory effects of adrenaline. The ability of adrenaline to induce the formation of a complex between the alpha 2-adrenoceptor and the inhibitory guanine nucleotide binding protein was examined in all three groups by assessment of the effect of mono and divalent cations and Gpp(NH)p on the displacement of [3H]yohimbine binding to platelet membranes by adrenaline. Coupling to adenylate cyclase was also assessed in separate studies of the inhibition by adrenaline of PGE1 stimulated cyclic AMP accumulation in whole platelets. Both the formation of the ternary complex and the inhibition by adrenaline of cyclic AMP accumulation was not significantly different in platelets sensitive or insensitive to adrenaline. These results suggest that inhibition of cyclic AMP alone does not explain the mechanisms of adrenaline induced platelet aggregation.

UI MeSH Term Description Entries
D009196 Myeloproliferative Disorders Conditions which cause proliferation of hemopoietically active tissue or of tissue which has embryonic hemopoietic potential. They all involve dysregulation of multipotent MYELOID PROGENITOR CELLS, most often caused by a mutation in the JAK2 PROTEIN TYROSINE KINASE. Disorder, Myeloproliferative,Disorders, Myeloproliferative,Myeloproliferative Disorder
D010974 Platelet Aggregation The attachment of PLATELETS to one another. This clumping together can be induced by a number of agents (e.g., THROMBIN; COLLAGEN) and is part of the mechanism leading to the formation of a THROMBUS. Aggregation, Platelet
D011942 Receptors, Adrenergic, alpha One of the two major pharmacological subdivisions of adrenergic receptors that were originally defined by the relative potencies of various adrenergic compounds. The alpha receptors were initially described as excitatory receptors that post-junctionally stimulate SMOOTH MUSCLE contraction. However, further analysis has revealed a more complex picture involving several alpha receptor subtypes and their involvement in feedback regulation. Adrenergic alpha-Receptor,Adrenergic alpha-Receptors,Receptors, alpha-Adrenergic,alpha-Adrenergic Receptor,alpha-Adrenergic Receptors,Receptor, Adrenergic, alpha,Adrenergic alpha Receptor,Adrenergic alpha Receptors,Receptor, alpha-Adrenergic,Receptors, alpha Adrenergic,alpha Adrenergic Receptor,alpha Adrenergic Receptors,alpha-Receptor, Adrenergic,alpha-Receptors, Adrenergic
D001792 Blood Platelets Non-nucleated disk-shaped cells formed in the megakaryocyte and found in the blood of all mammals. They are mainly involved in blood coagulation. Platelets,Thrombocytes,Blood Platelet,Platelet,Platelet, Blood,Platelets, Blood,Thrombocyte
D002850 Chromatography, Gel Chromatography on non-ionic gels without regard to the mechanism of solute discrimination. Chromatography, Exclusion,Chromatography, Gel Permeation,Chromatography, Molecular Sieve,Gel Filtration,Gel Filtration Chromatography,Chromatography, Size Exclusion,Exclusion Chromatography,Gel Chromatography,Gel Permeation Chromatography,Molecular Sieve Chromatography,Chromatography, Gel Filtration,Exclusion Chromatography, Size,Filtration Chromatography, Gel,Filtration, Gel,Sieve Chromatography, Molecular,Size Exclusion Chromatography
D004837 Epinephrine The active sympathomimetic hormone from the ADRENAL MEDULLA. It stimulates both the alpha- and beta- adrenergic systems, causes systemic VASOCONSTRICTION and gastrointestinal relaxation, stimulates the HEART, and dilates BRONCHI and cerebral vessels. It is used in ASTHMA and CARDIAC FAILURE and to delay absorption of local ANESTHETICS. Adrenaline,4-(1-Hydroxy-2-(methylamino)ethyl)-1,2-benzenediol,Adrenaline Acid Tartrate,Adrenaline Bitartrate,Adrenaline Hydrochloride,Epifrin,Epinephrine Acetate,Epinephrine Bitartrate,Epinephrine Hydrochloride,Epinephrine Hydrogen Tartrate,Epitrate,Lyophrin,Medihaler-Epi,Acetate, Epinephrine
D006165 Guanylyl Imidodiphosphate A non-hydrolyzable analog of GTP, in which the oxygen atom bridging the beta to the gamma phosphate is replaced by a nitrogen atom. It binds tightly to G-protein in the presence of Mg2+. The nucleotide is a potent stimulator of ADENYLYL CYCLASES. GMP-PNP,GMP-P(NH)P,Gpp(NH)p,Guanosine 5'-(Beta,Gamma-Imido)Triphosphate,Guanyl-5'-Imidodiphosphate,P(NH)PPG,Guanyl 5' Imidodiphosphate,Imidodiphosphate, Guanylyl
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000262 Adenylyl Cyclases Enzymes of the lyase class that catalyze the formation of CYCLIC AMP and pyrophosphate from ATP. Adenyl Cyclase,Adenylate Cyclase,3',5'-cyclic AMP Synthetase,Adenylyl Cyclase,3',5' cyclic AMP Synthetase,AMP Synthetase, 3',5'-cyclic,Cyclase, Adenyl,Cyclase, Adenylate,Cyclase, Adenylyl,Cyclases, Adenylyl,Synthetase, 3',5'-cyclic AMP
D000527 Alprostadil A potent vasodilator agent that increases peripheral blood flow. PGE1,Prostaglandin E1,Caverject,Edex,Lipo-PGE1,Minprog,Muse,PGE1alpha,Prostaglandin E1alpha,Prostavasin,Prostin VR,Prostine VR,Sugiran,Vasaprostan,Viridal,Lipo PGE1

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