Comparison of anxiolytic effects of allopregnanolone and diazepam on the elevated plus-maze in mice / 中国临床药理学与治疗学

ABSTRACT

To compare the anxiolytic effects of reduced metabolite of progesterone and benzodiazepine.Methods　The effects of allopregnanolone and diazepam on spontaneous locomotor activity and on exploration in the elevated plus-maze were studied in C57 mice 20 min after vehicle or drug intraperitoneal administration.Results Allopregnanolone (0.1 mg.kg-1,ip) elicited marked anxiolytic effects in terms of significantly reducing the latency to enter the open arm from (31.30±8.39)s to (8.80±6.00)s,(P<0.001),and significantly increasing both the number of open arm entries from 1.20 ± 0.42 to 4.80 ±1.75,(P<0.001) and the proportion of total time spent on the open arm from 7.13％ to 32.50％,(P<0.001).Meanwhile,the diazepam (0.25 mg·kg-1) produced a lower anxiolytic effect comparing to that of the allopregnanolone.Analysis of spontaneous locomotor activity showed while 0.5 mg·kg-1 of diazepam decreased the locomotor activity (P<0.01),neither 0.1 mg·kg-1 of allopregnanolone nor 0.25 mg·kg-1 of diazepam affect the locomotor activity score.Conclusion Together,these results provide evidence for differential behavioral actions of the neurosteroids and benzodiazepines.Since the allopregnanolone produce a selective anxiolytic effect without affecting the spontaneous locomotor activity,the allopregnanolone may be a better alternative for diazepam in treating anxiety.