Abstract
The non-selective vasodilating g -blocker carvedilol was found to inhibit platelet aggregation as well as thromboxane B 2 formation more effectively than propranolol. The antiaggregatory activity of carvedilol decreased, depending on the stimulus used, in the following rank order of potency (in parentheses the respective mean inhibitory concentrations of carvedilol and propranolol are given in w mol/l): PMA (19 and 34) > thrombin (55 and 77) > Ca 2+ -ionophore A23187 (58 and 81) > epinephrine (86 and 118). However, aggregation of platelets activated with ADP was not affected by carvedilol in concentrations up to 100 w mol/l. In platelets stimulated with thrombin, carvedilol (10 w mol/l) reduced thromboxane B 2 formation by 64%, whereas propranolol was ineffective at this concentration. Moreover, A23187-induced formation of thromboxane B 2 , not affected by propranolol, was completely blocked by 100 w mol/l carvedilol. In comparison to propranolol, the molecule of carvedilol is more lipophilic and possesses lower dipole moment and higher molar refractivity, thus penetrating into platelet membranes readily and in large quantities. The antiplatelet effect was assumed to result from interactions of carvedilol with membrane macromolecules (phospholipids, ion channels, enzymes, etc.) rather than from blockade of f - and g -adrenergic receptors.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.