Efficacy of choice testing to predict chronic ingestion of drinking solutions adulterated with chemicals

The feasibility of using a measure of palatability in a 2-bottle choice paradigm to determine detriments in fluid intake when unpalatable solutions containing drugs or chemicals were provided as a sole source of fluid was examined. Palatability measures obtained from testing various concentrations of quinine with water in a two-bottle choice paradigm were compared with intake of these same solutions when they were the sole fluid source for 20 consecutive days. Mice were observed to significantly avoid quinine solutions at concentrations as low as 0.0001 mg/ml in a choice situation while fluid intake was reduced in a forced drinking situation only at a concentration of 0.1 mg/ml. Palatability altered forced fluid intake only when quinine solutions comprised 20% or less of total intake in a choice situation. This approach was successfully employed to predict whether various concentrations of halogenated hydrocarbons could be administered in a repetitive forced drinking situation without reducing total fluid intake of mice.