Effects of adrenaline on human blood platelets

Abstract

SUMMARY1. Adrenaline at concentrations too low to cause aggregation of human platelets potentiates the aggregation by adenosine diphosphate. Noradrenaline has the same effect but is less active than adrenaline; isopropylnoradrenaline is inactive or inhibitory.2. The potentiation of adenosine diphosphate by catecholamines is blocked by the adrenergic ac-receptor antagonists phentolamine and dihydroergotamine but not by 2-halogenoethylamines or by adrenergic fl-receptor antagonists.3. Both the first and second phases of adenosine diphosphate aggregation are potentiated by catecholamines but the second phase more than the first.4. The release from the platelets of adenine nucleotides which is associated with the second phase of aggregation is also increased by adrenaline.

Adrenaline enhances in vitro platelet activation and aggregation in blood samples from ticagrelor‐treated patients

“…One option would be to transiently enhance platelet function until bleeding has stopped or until the operation is completed. Platelets express adrenergic receptors, and supplementation with adrenaline has previously been shown to potentiate ADP‐induced platelet aggregation in healthy subjects11 and in clopidogrel‐treated patients 13. In a study conducted on platelet‐rich from healthy subjects, the P2Y 12 ‐receptor antagonists ticagrelor, clopidogrel, prasugrel, and cangrelor were added in vitro and adrenaline supplementation (1 μmol L −1 ) was shown to restore ADP (5 μmol L −1 )‐induced aggregation with either P2Y 12 ‐receptor antagonist present 12.…”

“…Furthermore, only adrenaline was tested in the present study. Other clinically used adrenergic agents such as noradrenaline also need to be evaluated, although in vitro data suggest that noradrenaline is not as potent as adrenaline in inducing aggregation of untreated platelets 11, 15, 16…”

“…One potential method would be to temporarily enhance platelet activation and aggregation during surgery or until the bleeding has stopped. Supplementation with adrenaline, which is commonly used in cardiac surgery during and after cardiopulmonary bypass to maintain blood pressure, has previously been shown to potentiate platelet aggregation induced by ADP in healthy subjects11, 12 and in clopidogrel‐treated patients 13. In the present study, we hypothesized that adrenaline would potentiate ADP‐induced platelet aggregation and activation in patients with ongoing ASA and ticagrelor treatment, since the platelet membrane express adrenergic α 2A ‐receptors 11, 14, 15, 16.…”

Uptake, metabolism and release of [3H]‐adrenaline by human platelets

“…Human platelet-rich plasma containing citrate as anticoagulant was prepared as already described (Born & Cross, 1963;Mills & Roberts, 1967); the concentration of platelets was determined by counting under the phase-contrast microscope. Samples (2'5 ml) of platelet-rich plasma or of resuspended platelets were incubated at 370 C in a water bath without shaking for different times with added [3H]-adrenaline and/or with other substances, as described under Results.…”

“…Adrenaline causes human platelets to aggregate (Clayton & Cross, 1963) and potentiates the aggregating effect of other substances such as ADP (Mills & Roberts, 1967). Indirect evidence suggests that the aggregating effect of thrombin on human platelets is potentiated by adrenaline contained in them (Thomas, 1967).…”