Differential sensitivity to lithium's reversal of amphetamine-induced open-field activity in two inbred strains of mice

To determine whether genetic differences could contribute to the pharmacolo gical sensitivity of lithium chloride (LiCl) to reverse amphetamine-associa ted changes in behavior C57BL/6nCrlBR and C3H/HenCrlBR male mice were teste d for the ability of an acute dose of LiCl to reverse the locomotor enhanci ng effects of an acute dose of amphetamine. A series of experiments were co nducted that compared dose response of LiCl, chamber lighting conditions, a nd chamber shape on amphetamine-induced activity in two strains of mice wit h different genetic backgrounds. Acute amphetamine (3 mg/kg) increased loco motor activity in C7BL/6nCrlBR mice and LiCl (1-4 mEq/kg) blocked this effe ct. LiCl-induced changes in baseline activity seen at high doses of LiCl we re not seen for the low doses. The dark condition reduced time resting but chamber shape did not appear to alter results. In C3H/HenCrlBR mice, amphet amine did not significantly increase levels of activity but did decrease re aring behavior which suggests that genetic difference between C57BL/6nCrlBR and C3H/HenCrlBR mice may contribute to sensitivity to amphetamine. In sum , the ability of LiCl to reverse amphetamine-induced changes in locomotor a ctivity in C57BL/6nCrlBR mice may provide a useful model to study genetic a nd pharmacological aspects of psychiatric illnesses such as bipolar disorde r. (C) 2001 Elsevier Science B.V. All rights reserved.