The effect of an isoprenaline infusion on the splenic blood flow and intrasplenic platelet kinetics.
The effect of a constant isoprenaline infusion on the venous platelet count, splenic blood flow and intrasplenic platelet kinetics was investigated in 6 healthy male volunteers. The study was carried out using autologous 111In-labelled platelets and dynamic gamma camera imaging of the initial distribution of radiolabelled platelets between blood and splenic platelet pool. The isoprenaline infusions were administered i.v. over 30 min in a dose of 0.03 micrograms/kg/min. These infusions significantly increased the splenic blood flow and the size of the exchangeable splenic platelet pool. Concomitantly, there was a decrease of labelled as well as unlabelled platelets in the peripheral blood. The intrasplenic platelet transit time was not affected. Before start of infusion, the splenic blood flow was 6.1 +/- 2.9 (SD) % of total blood volume/min and the splenic platelet pool size 34 +/- 9 (SD) %. During infusion the corresponding values were 8.7 +/- 3.9 (SD) and 41 +/- 11 (SD), respectively. It is concluded that an i.v. infusion of isoprenaline enhances splenic pooling of platelets as a result of an increase in splenic blood flow.
D000328:Adult; D001792:Blood Platelets / Q000166:cytology / Q000502:physiology*; D006801:Humans; D007262:Infusions, Intravenous; D007545:Isoproterenol / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D010976:Platelet Count; D011877:Radionuclide Imaging; D012039:Regional Blood Flow / Q000187:drug effects; D013154:Spleen / Q000098:blood supply* / Q000000981:diagnostic imaging
D007545:Isoproterenol