Effects of 8-(N, N-Diethylamino)Octyl 3,4,5-Trimethoxybenzoate HCI (TMB-8) on Washed Blood Platelets with Special Reference to a Specific Loss of Serotonin^[*]

Summary

8-(N,N-diethylamino)octyl 3,4,5-trimethoxybenzoate HCl (TMB-8) has been used to indicate involvement of Ca⁺⁺ in platelet activities, but possible other effects have not been investigated. This study investigates TMB-8-induced leakage of cytoplasmic content and specific loss of one granule constituent, serotonin from washed platelets. TMB-8 concentrations above 0.5 mM block secretion initially and induce leakage after short time incubation. TMB-8 (0.15 mM) enhances a slow release of serotonin, but inhibits a slow release of low affinity platelet factor 4 antigen which take place when washed platelets are incubated at pH 7.4 and 37°C. These effects should be taken into consideration when TMB-8 is used as a calcium antagonist in platelets.

Key words

TMB-8 - Calcium antagonists - Platelet leakage - Serotonin loss - Platelet inhibitor

^* These results have been presented at the 71st Annual ASBC meeting in New Orleans, LA, June 1980 (Abstract Fed. Proc. 39: 2101).

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