Positive effects of β-amyrin on pentobarbital-induced sleep in mice via GABAergic neurotransmitter system

Sleep loss, insomnia, is considered a sign of imbalance of physiological rhythm, which can be used as preclinic diagnosis of various neuropsychiatric disorders. The aim of the present study is to understand the pharmacological actions of alpha- or beta-amyrin, natural triterpene compound, on the sleep in mice. To analyze the sleeping behavior, we used the well-known pentobarbital-induced sleeping model after single administration of either alpha- or beta-amyrin. The sleeping onset time was remarkably decreased and duration was prolonged by beta-amyrin (1, 3, or 10 mg/kg) but not by alpha-amyrin (1, 3, or 10 mg/kg). These effects were significantly blocked by GABA(A) receptor antagonist, bicuculline. Moreover, beta-amyrin increased brain GABA level compared to the vehicle administration. Overall, the present study suggests that beta-amyrin would enhance the total sleeping behavior in pentobarbital-induced sleeping model via the activation of GABAergic neurotransmitter system through GABA content in the brain. (C) 2015 Elsevier B.V. All rights reserved.