This study investigates the ability of lithium and acaffeine on both struggling responses and gastric lesions induced by immnobilization stress. When rats were exposed to immobilization stress, struggling responses such as tail flipping and vocalization, and defecation initially appeared, wheras a decrease of struggling responses with concomitant gastric lesions occurred later. Lithium choraide (50, 100 mg/kg i.p.) significantly attenuated these responses during immobilization stress in a dose-dependent manner. A potent adenosine A_1 receptor stimulant, N^6-cyclohexyl adenosine (CHA