Responsivity to water regulatory challenges in rats adapted to fluids adulterated with quinine or citric acid

Abstract

Ad lib ingestive behavior and reactivity to water regulatory challenges were examined in rats adpated to citric acid- or to quinine-adulterated fluids. Quinine drinkers were unlike citric acid subjects in being unresponsive to fluid deprivation and to the hypovolemia produced by polyethylene glycol (PEG). The effect during hypovolemia was evident when subjects had access to adulterated physiological saline, a solution more responsive to the PEG-induced need state, and quinine group behavior was not easily explained in terms of the tastes of quinine and saline combined together nor in terms of a posttreatment malaise effect. Substances that degrade the taste of water therefore do not exert uniform effects; bitter quinine appears to have some unique property that remains to be specified.