Cooling decreases the efficiency of prostaglandin inhibitors of platelet aggregation - a factor of possible relevance in cold induced pathology

The effect of temperature on ADP-induced platelet aggregation and on its inhibition by certain prostaglandins (PGI₂, PGE₁ and 6ketoPGE₁) was investigated. With all three prostaglandins there was progressively less inhibition of aggregation as the temperature decreased below 37°C. This phenomenon was more extensively investigated using a 10°C temperature difference (37°C and 27°C). The diminished anti-aggregatory activity at 27°C could to some extent be corrected by increasing the concentration of the inhibitors or by extending the period of incubation prior to addition of ADP. Intraplatelet c AMP concentration was found to be significantly higher after incubation with PGI₂ at 27°C than at 37°C. The possible relationship of these observations to the cold-induced disorders such as Raynaud's phenomenon is discussed.