An in vitro study of adrenaline effect on human erythrocyte properties in both gender

Article type: Research Article

Authors: Hilário, Sandra | Saldanha, Carlota | Martins e Silva, J.

Affiliations: Institute of Biochemistry, University of Lisbon, Faculty of Medicine, Av. Prof. Egas Moniz 1649‐028 Lisboa, Portugal Tel.: +351 21 7985136; Fax: +351 1 7939791; E‐mail: [email protected]

Abstract: The possibility that erythrocytes may function as a reservoir for noradrenaline and adrenaline and as a modulator of circulating catecholamine concentrations had been suggested. The aim of this work was to study the adrenaline effect on erythrocyte membrane fluidity, acetylcholinesterase (AChE) enzyme activity, P50 and erythrocyte deformability and also to verify if the role of adrenaline on erythrocyte properties is sex‐dependent. Blood samples from 42 healthy donors were obtained, and its aliquots incubated 30 min without (control) and with 10−5 M concentrations of adrenaline alone (A1) and adrenaline with an α and an β‐blocker (A2). Results demonstrate that initial AChE values in female are higher (p≤0.01) than male values. In female, adrenaline decreases AChE activity either when α and β‐adrenergic receptors are blocked (p≤0.01) or when they are not. In male, adrenaline increases AChE activity when none of adrenergic receptors are blocked. Control values of male and female erythrocyte membrane fluidity are very similar but behaviour became differently (p≤0.05) when adrenaline is present because it decreases male and increases female values. Gender differences in erythrocyte deformability are verified at high shear stress values (p≤0.02). In female we have also registered the existence of an inverse significant correlation (r=−0.62) between membrane rigidity and AChE activity in A2 values. Adrenaline increases p50 values (p≤0.03) in both sexes. Peripheral blood film has shown echinocytes when adrenaline 10−5 M is present. We conclude that in this in vitro study sex‐related differences in erythrocyte acetylcholinesterase enzyme activity, membrane fluidity and erythrocyte deformability under adrenaline influence were found.

Keywords: Adrenaline, erythrocyte, erythrocyte membrane fluidity, acetylcholinesterase enzyme activity, P[TeX:] $_{50}$, erythrocyte deformability, gender

Journal: Clinical Hemorheology and Microcirculation, vol. 28, no. 2, pp. 89-98, 2003