Stereoselectivity of arrhythmogenic effect of praziquantel in conscious rabbits
Qian, Y.S.; Quan, Y.Z.
Zhongguo Yao Li Xue Bao 10(3): 245-248
1989
ISSN/ISBN: 0253-9756 PMID: 2609997 Document Number: 143
Praziquantel (PQT) is a chiral compound with an asymmetric center at the 11 b-position. The recemic mixture is usually used as an antischistosomal drug, however the antischistosomal activity is mainly concentrated in the R (-) -enantiomer. This study was undertaken to investigate the stereoselectivity of the arrhythmogenic effect of PQT in conscious rabbits. Arrhythmias, as well as bradycardia, were induced in rabbits by iv (.+-.)PQT or its enantiomers at 45 mg/kg. The frequency of ectopic rhythms in the (+), (.+-.) and (-) PQT groups were 100, 60 and 20%, respectively. Statistically, the frequency of ectopic rhythms in the (+) PQT group was significantly higher than those in the (-) PQT group and in the (.+-.) PQT group, although there was no significant difference between the (.+-.) and (-) PQT groups. The severity of the arrhythmias induced by (+) PQT was much higher than that induced by (-) PQT. The bradycardia action of (+) PQT was much more intense than that of (-) PQT. (.+-.) PQT or its enantiomers (icv) at a dose of 2 or 3 mg/kg also induced arrhythmias. The frequency of ectopic rhythms in the (+) PQT group was significantly higher than that in the (-) PQT group. The results suggest that there is a stereoselectivity of the arrhythmogenic effects of PQT in rabbits. Arrhythmias induced by PQT may partly mediate via the central nervous system, and the arrhythmogenic effects of (.+-.) PQT may be caused mainly by (+) PQT.
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