Objective To study the expression of gama-aminobutyric acid transporter-1 (GAT-1) mRNA and protein in the brain stem of insomnia model rats.Methods Thirty-six SD rats were randomly divided into three groups: insomnia model, normal saline control and diazepam interference. A rat insomnia model was prepared by intraperitoneal injections of ρ-chlorophenylalanine (PCPA). The expression of GAT-1 mRNA and protein in the brainstem were detected by RT-PCR and Western blot.Results Compared with the control group, the expression of GAT-1 mRNA and protein in the model and interference groups was down-regulated (P<0.01). The interference group showed significantly lower expression of GAT-1 than the model group (P<0.01).Conclusions The down-regulation of the expression of GAT-1 may be involved in the body's protective mechanisms after insomnia. Diazepam can decrease GAT-1 expression, possibly thus providing its hypnotic function.