STRAIN DIFFERENCES IN CONSUMPTION OF SALINE SOLUTIONS BY MICE

Intake of saline (NaCl) solutions and water by males of two inbred strains of mice [C57BL/6J (C57) and 129/J] were examined using 48-h, two-bottle preference tests. There was a large strain difference in saline intake: at moderate concentrations (0.075-0.150 M) C57 mice tended to reject saline relative to water, whereas 129/J mice preferred it. Both strains of mice increased their intake of saline following lasix-induced sodium depletion and the preference exhibited by 129/J mice for 0. 1 5 M NaCl was eliminated following LiCl toxicosis. The rejection of moderate concentrations of saline by C57 was shown to be due, in part at least, to prior exposure to iso- or hypertonic saline solutions: C57 mice that had no prior exposure to saline exhibited a greater intake of saline than C57 mice previously exposed to 0.30 M NaCl. Saline preferences of the 129/J mice were not affected by prior exposure to 0.30 M NaCl. Thus, the strain difference in mouse salt preference is due in part to postingestional consequences of saline consumption in C57 but not 129/J mice.