Does meta-chlorophenylpiperazine (mCPP) activate human platelets?
mCPP (meta-chlorophenylpiperazine), an agonist at serotonin (5-hydroxytryptamine, 5-HT) 5-HT2 receptors, has been used as a probe of serotonergic function. We assessed its effect on platelet activation by measuring median platelet volume (MPV), the Sonoclot (SCT) pattern and plasma and intraplatelet serotonin. (a) In vitro study: MPV was measured (n = 7) using a high-resolution channelyzer: Saline (median and range (5.23 fl; 5.10-6.18) vs. mCPP (5.36; 5.10-6.44) P = 0.03; ADP (5.42; 5.29-6.44) vs. ADP + mCPP (5.67; 5.42-6.63) P = 0.02; mCPP (5.36; 5.10-6.44) vs. ADP + mCPP (5.67; 5.42-6.63) P = 0.02. Therefore, mCPP increases the MPV and enhances the effect of ADP. (b) In vivo study: The SCT time to inflection (TI) and time to peak (TP) were measured following the oral administration of mCPP (0.5 mg/kg) or aspirin (300 mg) (n = 10). Ingestion of mCPP significantly shortened TI and TP indicating platelet activation. TI: 0 h (mean +/- SD: 10.2 +/- 2.0 min) vs. 6 h (9.3 +/- 1.5) P = 0.03; TP: 0 h (31.9 +/- 7.6) vs. 6 h (23.1 +/- 2.9) P = 0.01. Aspirin had no effect on TI or TP. There were no significant changes in plasma and intraplatelet 5-HT. It is concluded that mCPP activates human platelets via 5-HT receptors.
Frampton
A E
AE
Academic Department of Accident and Emergency Medicine, Imperial College, St. Mary's Hospital, London, W2 1NY, UK.
Andrews
J C H
JC
Parfitt
A
A
Jagroop
I A
IA
Mikhailidis
D P
DP
Henry
J A
JA
D000244:Adenosine Diphosphate / Q000008:administration & dosage; D001780:Blood Coagulation Tests; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D010879:Piperazines / Q000494:pharmacology*; D015539:Platelet Activation / Q000187:drug effects*; D012701:Serotonin / Q000378:metabolism; D058826:Serotonin 5-HT2 Receptor Agonists; D013997:Time Factors
D010879:Piperazines; D058826:Serotonin 5-HT2 Receptor Agonists; D012701:Serotonin; D000244:Adenosine Diphosphate; C015068:1-(3-chlorophenyl)piperazine