Antagonism of Morphine and of Reserpine by Levorotatory and Dextrorotatory Isomers of 2,2-Diphenyl-4-(2-Piperidyl)-1,3-Dioxolane HCl

Abstract

Discussion and summary

The d (dexoxadrol and the l (levoxadrol) isomers of the lower melting racemic modification of 2,2-diphenyl-4- (2-piperidyl) −1,3-dioxolane HCl have surprisingly different pharmacologic properties.

Dexoxadrol, but not levoxadrol, produces “hyperalgesia'or “hyperacuity'as evidenced by shortening of the reaction time of mice to a thermal stimulus and increasing the number of writhes following the intraperitoneal administration of phenylquinone. Tachyphylaxis does not occur to the “hyperalgesia'produced by dexoxadrol.

Dexoxadrol, but not levoxadrol, antagonizes the analgesic activity of morphine in mice subjected to a thermal stimulus. Both are ineffective in those administered phenyl-quinone. This difference is possibly related to differences between visceral and somatic pain.

Both isomers antagonize the effects of reserpine as measured by the reversal of the reserpine induced prolongation of hexobarbital hypnosis and the reserpine induced prolongation of the reaction time of mice exposed to a thermal stimulus.

This unusual “hyperalgesia'or “hyperacuity'property of dexoxadrol suggests that it may be an agent which will increase awareness.