Taste aversions conditioned with gamma radiation: attenuation by area postrema lesions in rats

The role of the area postrema in radiation induced taste aversions in rats was examined. One group of rats received lesions of the area postrema, another group was given sham lesions and a third group received no surgery. These three groups of rats were then given one pairing of 1 h access to a novel 0.15% sodium saccharin solution followed immediately with exposure to 200 rad gamma radiation. A fourth group of rats with area postrema lesions was given 1 h access to saccharin followed by a sham irradiation procedure. Four days later all groups were given daily two bottle preference tests (saccharin vs water) on 5 consecutive days. The groups with sham lesions or no surgery displayed a strong aversion to saccharin on all 5 test days. The two area postrema lesioned groups displayed a moderate and increasing preference for saccharin over the 5 day test period. The lesioned group given radiation treatment showed a weak but significant aversion (P less than 0.05) to saccharin on the first test day, when compared to the lesioned rats not given radiation treatment. Thus, lesions of the area postrema strongly attenuated the radiation induced taste aversions, but did not completely abolish them.