Loss and recovery of sodium-salt taste following bilateral chorda tympani nerve crush.

The ability of the gustatory system to recover following peripheral nerve injury was investigated in adult hamsters. A conditioned taste aversion paradigm was utilized to test sodium salt-taste function after bilateral crush of the chorda tympani nerve and after nerve regeneration. Bilateral chorda tympani crush abolished expression of a previously learned conditioned taste aversion to 0.1 M NaCl. At 10 to 16 weeks following surgery, the hamsters were reconditioned three times to 0.1 M NaCl. The hamsters were able to relearn the conditioned taste aversion and by 16 weeks, the crush and sham groups showed equally strong and specific aversions to 0.1 M NaCl. A second surgery to cut the regenerated chorda tympani nerves resulted, again, in the loss of expression of the conditioned taste aversion. Thus, regenerated chorda tympani nerves are capable of carrying the information needed to form a conditioned taste aversion specific for sodium salts in the adult hamster.