“ Cocaine differentially potentiated the effects of the sympathomimetic amines used such that … changed from xylazine greater than (-)-adrenaline greater than (+)-noradrenaline greater than (-)-metaraminol greater than or equal to (-)-noradrenaline greater than or equal to dopamine, to … greater than (-)-metaraminol greater than dopamine greater than or equal to (+)-noradrenaline.”