• Muhammad Shamaun Razi
  • Idrees Farooq Butt
  • Muhammad Ayub
  • Muhammad Aslam
  • Waqas Hameed
  • Ahmed Badar
  • Muhammad Nasir Afzal


Background: Efficient hemostasis in human body depends on a complicated series of events which actively involve blood platelets. Platelets exhibit diverse responses in a variety of agonists. In vivo, most of the agonists act in synergism, causing aggregation of platelets. Methods: In this study, the synergism between ADP – Epinephrine and Epinephrine – Collagen has been determined by means of turbidometric method, which measures changes in optical density of platelet suspension. The study was carried out at the department of Hematology, Armed Forces Institute of Pathology, Rawalpindi. The subthreshold concentrations of each of the agonists were established with the help of dose response curve. By adding these agonists in subthreshold concentrations, the synergism between ADP – Epinephrine and Epinephrine – Collagen was determined. Results: The combinations of these agonists in subthreshold levels showed the synergistic responses in causing platelet aggregation. Conclusion: These findings indicate that the optimal platelet aggregation does occur between the above mentioned pairs of agonists even when each of the agonist is added to the other in subthreshold doses. Keywords: Platelet aggregation, agonist, synergism, Adenosine diphosphate, Collagen, Epinephrine


Corash L. The relationship between megakaryocyte ploidy and platelet volume. Blood Cells 1989; 15: 81-107.

Butt IF, Aslam M, Khan FA, Ayub M. Plasma insulin and platelet functions in diabetes mellitus. JCPSP 2000; 10: 182-4.

Nachmias VT. Platelet and megakaryocyte shape change: triggered alterations in the cytoskeleton. Sem Hematol 1983; 20: 261-81.

Libby P, Warner SJ, Salomon RN, Birinyi LK. Production of platelet derived growth factor-like mitogen by smooth muscle cells from human atheroma. N Engl J Med 1988; 318: 1493-8.

Ishii, Umeda F, Hashimoto T, Nawata H. Increased intracellular calcium mobilization in platelets from patients with type 2 (non-insulin dependent) diabetes mellitus. Diabetologia 1991; 34: 332-6.

Shukla SD, Paul A, Klachko DM. Hypersensitivity of diabetic human platelets to platelet activating factor. Thromb Res 1992; 66: 239-46.

Kunisaki M, Umeda F, Inoguchi T, Watanaba J, Nawata H. Effects of Vit-E administration on platelet function in diabetes mellitus. Diabet Res 1990; 14: 37-42.

Haung EM, Detwiler TC. Characteristics of the synergistic actions of platelet agonists. Blood 1981; 57(4): 685-91.

Kinlough-Rathbone RL, Packham MA, Mustard JF. Synergism between platelet aggregating agents: The role of the arachidonate pathway. Thromb Res 1977; 11: 567-80.

Born GVR, Cross MJ. The aggregation of blood platelets. Nature 1963; 168: 178-95.

Roper P, Drewinko B, Hasler D, Johnston D, Hester J, Freireich EJ. Effects of time, platelet concentration and sex on the human platelet aggregation response. Am J Clin Pathol 1979; 71: 263-8.

Michal F, Motamed M. Shape change and aggregation of blood platelets: interaction between the effects of adenosine diphosphate, 5-hydroxytryptamine and adrenaline. Br J Pharmacol 1976; 56: 209-18.

Mills DCB, Roberts GCK. Effects of adrenaline on human blood platelets. Am J Physiol 1967; 193: 443-53.

Osmani AH, Clare KA, Scrutton MC. Synergistic interaction and platelet inhibitory agents. Thromb Res 1983; 31: 665-74.

Ardlie NG, Glew G, Schwartz CJ. Influence of catecholamine on nucleotide-induced platelet aggregation. Nature 1966; 5060: 415-7.

Vanags DM, Rodgers SE, Duncan EM, Lloyd JV, Bochner F. Potentiation of ADP induced aggregation in human platelet-rich plasma by 5-hydroxytryptamine and adrenaline. Br J Pharmacol 1992; 106: 917-23.

Huang EM, Detwiler TC. Characteristics of the synergistic actions of platelet agonists. Blood 1981; 57: 685-91.

Ware JA, Smith M, Salzman EW. Synergism of platelet-aggregating agents. J Clin Invest 1987; 80: 267-71.

Hallam TJ, Scrutton MC, Wallis RB. Synergistic responses and receptor occupancy in rabbit blood platelets. Thromb Res 1982; 27: 435-45.

Smith JB, Selak MA, Dangelmaier C, Daniel JL. Cytosolic calcium as a second messenger for collagen-induced platelet responses. Biochem J 1992; 288: 925-9.

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