Jules B. LaPidus

The isomers of cocaine and tropacocaine: Effect on 3H-catecholamine uptake by rat brain synaptosomes

Abstract Compared to (+)- pseudo cocaine, (−)-cocaine was 20 times more potent in inhibiting uptake of 3 H-norepinephrine ( 3 HNE) by cortical synaptosomes and 66 times more potent with respect to 3 H-dopamine ( 3 HDA) uptake by striatal synaptosomes. Although the tropacocaine isomers were equipotent as inhibitors of 3 HNE uptake in the cortex, tropacocaine was 3.9 times more potent as an inhibitor of 3 HDa uptake in the striatum than pseudo tropococaine. A major known cocaine metabolite, benzoylecgonine failed to inhibit the accumulation of 3 HNE and 3 HDA by synaptosomes from the cortex and striatum, respectively. The implications of these findings in relation to the motor stimulation seen with (−)-cocaine, (+)- pseudo cocaine and benzoylecgonine in rats are discussed.

Effects of ephedrine isomers on myocardial catecholamines

Abstract All ephedrine isomers except D(−)-ephedrine, cause release of similar amounts of norepinephrine from the isolated rabbit-heart. D(−)-ephedrine causes release of substantially larger amounts of norepinephrine. Perfusion with D(−)-ephedrine and D(−)-pseudoephedrine increases the norepinephrine content of the heart to essentially the same extent, but L(+)-ephedrine and L(+)-pseudoephedrine cause no significant increase.

The stereoselective inhibition of lipolysis by nonphenolic phenethylamines

Abstract Inhibition of norepinephrine-induced lipolysis by the steroisomers of ephedrine and phenyl-2-piperidyl carbinol and the diastereomers of 8-hydroxy-6,7-benzomorphan was investigated in rat adipose tissue, in vitro. Relative inhibitory actions of stereoisomers were observed to be 1R,2S > 1S,2R = 1R,2R = 1S,2S. In each series, the erythro-configuration or 1R,2S enantiomer was best accomodated by the adrenergic adipose tissue receptor system.

Supersensitivity of the cat nictitating membrane to dopamine

Abstract The classical theory of Easson and Stedman6 emphasizes a 3 point attachment of a catecholamine with a hypothetical receptor, and suggests that the desoxy derivative of an amine should act like its corresponding L(+)-isomer. Our observations on normal and sensitized tissue tend to be compatible with this theory in that dopamine, which has no hydroxyl group on the beta - carbon, was found to behave more like L(+)-norepinephrine where the hydroxyl group of the beta -carbon is presumably in an unfavorable position for attachment to the receptor than like D(-)-norepinephrine with a favorably placed hydroxyl group on the beta carbon.