[The role of the vagus nerves in the manifestations of neophobia and conditioned-reflex taste aversion].

Vagotomized rats given a choice between water and an unfamiliar 0.2% saccharin solution ingest comparable amounts of both fluids over 2.5 weeks of testing. Saccharin intake in sham-operated rats grows steadily (attenuation of taste neophobia), with water intake being unchanged. After the pairing of water intake with rotation saccharin intake in vagotomized rats grows and in sham-operated animals decreases significantly, whereas water intake in the latter increases sharply. Thus, the rats with retained vagal innervation exhibit aversion to saccharin, substance with an unfamiliar taste, but not to water paired with a discomfort. After two-week elimination of neophobia to saccharin, the pairing of water intake with rotation brings into the acquisition of aversion to water in the first days of choice testing in sham-operated rats; similar aversion in vagotomized rats appears with retardation (on the 4th to 6th day).