The effect of delta1-tetrahydrocannabinol on the uptake of [3H]-(minus)-noradrenaline by the isolated perfused heart of the rat.

Forty-eight isolated rat hearts were perfused with Krebs solution and with [(3)H]-(-)-noradrenaline ([(3)H]-NA) containing 4.5 nCi/ml in 50 ng/ml, as described by Iversen (1963). To groups of six, cocaine was added to [(3)H]-NA in concentrations of 400 nM, 2 and 10 muM. To the rest Tween 80, 25 mug/ml was added to [(3)H]-NA and in three groups Delta(1)-THC additionally in concentrations of 560 nM and 2.8 or 14 muM. Cocaine caused a linear concentration-related inhibition of uptake; Tween caused a 38.7% inhibition; THC caused additionally a linear concentration-related inhibition.