title: Role of alpha 2-adrenergic receptor in platelet activation during insulin-induced hypoglycemia in normal subjects.
abstract: The effects of alpha 2-adrenergic-receptor blocker mianserin on the responses of blood glucose, plasma beta-thromboglobulin (beta-TG), and various counterregulatory hormones to insulin-induced hypoglycemia were studied in nine healthy male subjects. The alpha 2-adrenoceptor-blocking action of mianserin was confirmed by its inhibitory effect on platelet activation in vitro. Mianserin was given orally 90 min before insulin injection; the same study without mianserin was performed on another day as the control study. The time courses of blood glucose and serum C-peptide (0, 20, 45, and 180 min after the insulin injection) were identical in both studies, indicating that mianserin has no effect on these parameters. However, a significant increase of beta-TG at 45 min after insulin injection was completely suppressed by the administration of mianserin (mean +/- SE, 68.5 +/- 6.0 vs. 28.8 +/- 7.6 ng/ml, n = 6, P less than .05). No significant differences were obtained between the two studies in the responses of plasma or serum catecholamines, cortisol, glucagon, growth hormone, thromboxane B2, and 6-ketoprostaglandin F1 alpha. These results suggest that epinephrine is responsible for some, if not all, of the beta-TG release from the platelets during insulin-induced hypoglycemia.
mesh_terms: D000328:Adult; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D004837:Epinephrine / Q000494:pharmacology; D006801:Humans; D007003:Hypoglycemia / Q000097:blood*; D007213:Indomethacin / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D008803:Mianserin / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000494:pharmacology; D001620:beta-Thromboglobulin / Q000097:blood
chemical_list: D007328:Insulin; D011942:Receptors, Adrenergic, alpha; D001620:beta-Thromboglobulin; D008803:Mianserin; D012701:Serotonin; D007213:Indomethacin; D004837:Epinephrine