Secoverine selectively antagonizes muscarinic effects in various in vivo preparations

Time-activity studies of secoverine and atropine were made with respect to mydriasis and oxotremorine-induced salivation, lacrimation and tremors. Marked differences were found in the anticholinergic activity relation between secoverine and atropine for various tissues. These differences remained present at all time intervals, which excludes a pharmacokinetic explanation. It may be concluded that secoverine possesses a different affinity for various muscarinic receptors.