Effect of chlorpromazine treatment on monoamine oxidase activity in platelets isolated by the Corash method

The effect of chlorpromazine treatment on platelet monoamine oxidase (MAO) activity was compared in platelets isolated by the Corash method, which harvests essentially all the platelets in a blood sample, and a single centrifugation method, which yields 45-65% of the platelets. A highly significant decrease in platelet MAO activity following chlorpromazine was found in platelets obtained from the same subjects by both methods. The decrease observed by the two methods was significantly correlated. These results indicate the degree of decrease in MAO activity associated with chlorpromazine is not due to isolation of a subpopulation of platelets with low MAO activity by the single centrifugation method.