Comparing oral lithium carbonate and intraperitoneal lithium chloride chronic administrations on rats' activity...

This study compares the effects produced by two modalities of lithium administration on rats' activity levels. Lithium was administered for 21 days either as carbonate in the diet (2 g in 2 liters of water and 1,500 g lab chow) or as chloride through single daily intraperitoneal injections (1 mEq/kg LiCl). Both treatments resulted in similar decreases in spontaneous activity and exploratory behavior, as recorded in an open field with a hole-board. Neither treatment influenced the amount of food consumed on a daily basis nor the rate of growth as manifested by weight gains over the period considered, suggesting that these treatments were not adversely affecting the animals' health. Both treatments increased water intake over control levels, this effect being most marked with the diet lithium carbonate administration, particularly during the second week of treatment. This latter modality of lithium administration, but not the injections of lithium chloride, significantly increased NaCl intake over control levels.