Influence of adrenergic neuron blocking agents on the adrenaline-induced platelet reactions.
Adrenaline causes aggregation of human blood platelets through stimulation of alpha-adrenoceptors resembling the alpha 2-type. Alpha-adrenoceptor blocking agents inhibit specifically the adrenaline-induced platelet reactions. The adrenaline-induced aggregation of human blood platelets was inhibited specifically by adrenergic neuron blocking agents such as guanoxan, guanclofine and guanethidine. Guanoxan (I50 = 0.6 mu mol/l) was about three orders of magnitude more effective than guanethidine, guanclofine occupied a median position. The compounds tested inhibited the ADP- and collagen-induced aggregation at relatively high concentrations. This is probably due to non-specific membrane effects. The known alpha-adrenolytic effect of guanoxan is believed to be mediated mainly by alpha 2-adrenoceptors.
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D004837:Epinephrine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D006145:Guanethidine / Q000494:pharmacology; D006146:Guanidines / Q000494:pharmacology; D006801:Humans; D010974:Platelet Aggregation / Q000187:drug effects*
D000319:Adrenergic beta-Antagonists; D006146:Guanidines; C035768:guanclofine; D004837:Epinephrine; D006145:Guanethidine