The mechanism of alteration of monoamine metabolism in brain regions in marble burying behavior-isolated housing mice and effect of Oren-gedoku-to onthis alteration

The mechanism of the alteration in marble burying behavior-isolated housing (MBB-IH) mice was investigated. The determination of hypothalamus monoamin e and serum corticosterone contents indicated that MBB-IH mice readily resp onded to the stress stimuli in conditioned fear stress. Six drugs, such as buspirone (10 mg/kg, p.o.), zimelidine (10 mg/kg, pc.), clomipramin (10 mg/ kg, p.o.), yohimbine (5 mg/kg, pc.), ethyl beta-carboline-3-carboxylate (be ta-CCE, 5 mg/kg,pc.) and flumazenil (15 mg/kg, p.o.) were singly and/or thr ee times administered to MBB-IH mice. Their inhibitory activity on the MBB- IH mice was considered by the use of activity profiles consisting of sponta neous locomotor activity, marble burying behavior and hypothalamus monoamin e content. Using these profiles, we calculated the activities as vector in three-dimensional space, and compared the distance from the control point ( DCP). DCPDOPAC and DCP5-HIAA were shortened by single administration of bet a-CCE and flumazenil. Oren-gedoku-to (30 and 300 mg/kg, p.o.) shortened the DCPDOPAC and DCP5-HIAA similarly to beta-CCE. The blended crude drugs in O ren-gedoku-to, Coptis rhizome (636.0 mg/kg, p.o.), Scutellaria root (644.4 mg/kg, p.o.) and Gardenia fruit (894.8 mg/kg, p.o.) shortened the DCPDOPAC Coptis rhizome and Scutellaria root also shortened the DCP5-HIAA These resu lts suggest that GABA neuron function intensely affects the alteration of M BB-IH and Oren-gedoku-to has the intrinsic benzodiazepine-like activity.