Pharmaceutical biology

A Scutellaria baicalensis radix water extract inhibits morphine-induced conditioned place preference.

PMID 25068674


Scutellaria baicalensis Georgi (Lamiaceae) has been used as a traditional herbal preparation for the treatment of neuropsychiatric disorders in Asian countries for centuries. To evaluate the effects of S. baicalensis on morphine-induced drug dependence in rats. In order to evaluate the effect of S. baicalensis and baicalin on morphine-induced dependence-like behavior, a water extract of S. baicalensis [500 mg/kg, intraperitoneally (i.p.)] or baicalin (50 mg/kg, i.p., a flavonoid found in S. baicalensis) was administered prior to morphine injection [5 and 2.5 mg/kg, respectively, subcutaneously (s.c.)] to rats for 8 and 4 d, respectively. Morphine-induced conditioned place preference was assessed by measuring the time spent in a drug-paired chamber. The effect of S. baicalensis on dopamine receptor supersensitivity (locomotor activity) and dopamine agonist-induced climbing behavior due to a single apomorphine treatment (2 mg/kg, s.c.) was also measured. At 50 mg/kg, a water extract of S. baicalensis decreased morphine (5 mg/kg)-induced conditioned place preference by 86% in rats. Apomorphine (2 mg/kg)-induced locomotor activity (dopamine receptor supersensitivity) in rats and climbing behavior in mice were attenuated after pretreatment with 500 mg/kg of S. baicalensis water extract by 41% and 56%, respectively. In addition, baicalin-reduced morphine-induced conditioned places preference by 86% in rats at 50 mg/kg. These results suggest that S. baicalensis can ameliorate drug addiction-related behavior through functional regulation of dopamine receptors.

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