α₂-Adrenoreceptor Status of Human Platelet Subpopulations Separated by Continuous Flow Electrophoresis

Summary

Human platelets were separated into subpopulations using continuous flow electrophoresis, which uses electrophoretic mobility as the separative parameter. The platelets with the greatest electrophoretic mobility showed higher amounts of total sialic acid than the less electrophoretically mobile subpopulation (74.3 ± 18.2 nmol/10⁹ platelets vs. 49.2 ± 20.1 nmol/10⁹ platelets, p <0.05 paired Student’s t-test). Furthermore, neuraminidaselabile sialic acid was also elevated in the more electrophoretically mobile platelet subpopulation (29.1 ± 6.0 nmol/10⁹ platelets vs. 21.8 ± 10.4 nmol/10⁹ platelets, p <0.05 paired Student’s t-test). We also found that the sialic acid enriched platelet subpopulation had more α₂-adrenoreceptors than the less electrophoretically mobile platelets (457 ± 104 vs. 302 ± 164 receptors per cell, p <0.05 paired Student’s t-test).

• References

• 1 O’Brien JR. Variability in the aggregation of human platelets by adrenaline. Nature 1964; 202: 1188-1190
• 2 Mills DCB. Initial biochemical responses of platelets to stimulation. Ciba Foundation Symposium, No. 35. Born GVR. (ed). Elsevier/North Holland; Amsterdam: 1975: 153-167
• 3 Clare KA, Scrutton MC, Thompson NT. Effects of a-adrenoreceptor agonists and of related compounds on aggregation and adenylate cyclase activity in human plateles. Br J Pharmacol 1984; 82: 467-476
• 4 Rao AK, Willis J, Kowalska MA, Wachtfogel YT, Colman RW. Differential requirements for platelet aggregation and inhibition of adenylate cyclase by epinephrine: Studies of a familial platelet α₂ adrenergic receptor defect. Blood 1988; 71: 494-501
• 5 Swart SS, Pearson D, Wood JK, Barratt DB. Functional significance of the platelet α₂ adrenoreceptor: Studies of patients with myeloproliferative disorders. Thromb Res 1984; 5: 531-541
• 6 Weiss RJ, Tobas M, Wertz CE, Smith CB. Platelet α₂ adrenoreceptorsin chronic congestive heart failure. Am J Cardiol 1983; 52: 101-105
• 7 Weiss RJ, Smith CB. Altered platelet α₂ adrenoreceptors in patients with angina pectoris. J Am Coll Cardiol 1983; 2: 631-637
• 8 Wachtfogel NT, Musias J, Jenkin R, Niewrarowski S, EdmundS H, Colman RW. Loss of platelet α₂ adrenergic receptors during simulated extracorporal circulation: Prevention with prostaglandin E1. J Lab Clin Med 1985; 105: 601-607
• 9 Cowen P, Elliot JM, Fraser S, Stump K. Effect of blood loss on platelet α₂ adrenoreceptors. Abstract to British Pharmacological Society Meeting, Leicester. 1983
• 10 Elliot JM. Blood donations and platelet α₂ adrenoreceptors. Personal communication. 1987
• 11 Crook M, Crawford N. Platelet surface charge heterogeneity: Characterisation of human platelet subpopulations separated by high voltage continuous flow electrophoresis. Br J Haematol 1988; 69: 265-273
• 12 Crook M, Crawford N. Electrokinetic and functional heterogeneity of circulating human platelets: Separation of subpopulations by continuous flow electrophoresis after taxol stabilization. Biochim Biophys Acta 1989; 194: 2619
• 13 White JG, Rao GH. Effects of a microtubule stabilizing agent on the response of platelets to vincristine. Blood 1982; 60: 474-479
• 14 White JG, Rao GH. Influence of a microtubule stabilizing agent on platelet structural physiology. Am J Pathol 1983; 112: 207-217
• 15 Boon NA, Elliot JM, Grahame-Smith DG, ST John-GreenT, Stump K. A comparison of α₂-adrenoreceptor binding characteristics of intact human platelets identified by [³H]-yohimbine and [³H]-dihydroergocryptine. J Auton Pharmacol 1983; 3: 89-95
• 16 Warren L. The thiobarbitrate acid assay of sialic acids. J Biol Chem 1959; 234: 1971-1975
• 17 Skoza L, Mohos S. Stable thiobarbitrate acid chromophore with dimethyl sulphoxide. Biochem J 1959; 159: 457-462