Sex differences in conditioned taste aversion and in the effects of exposure to a specific pulsed magnetic field in deer mice Peromyscus maniculatus

Although conditioned taste aversion (CTA) has been investigated and describ ed in laboratory rodents and domestic animals, less is known regarding wild rodents. Here, we describe CTA in males and females of a "wild" species of rodent, the deer mouse (Peromyscus maniculatus). In addition. as CTA has o ften been induced by exposure to intense electromagnetic, X or gamma, radia tion, in a second study, we also investigated the effects of a specifically designed, pulsed extremely low-frequency and low-intensity magnetic field on the flavor preferences of male and female deer mice. The results of thes e investigations showed that: (i) deer mice quickly developed a marked CTA for a novel flavor after a single pairing with LiCl; (ii) although the inte nsity of the CTA was the same in males and females, there was a sex differe nce in the duration of the flavor aversion, with males displaying it for a longer period (4 days) than females (3 days); (iii) both males and females showed a rapid and complete extinction of the aversion, in contrast to what has been reported for laboratory rodents; (iv) there was no recovery of CT A on re-test 10 days after extinction; (v) neither male or female deer mice developed a taste aversion as a consequence of exposure to a weak electrom agnetic field: and (vi) there was a sex difference in response to the magne tic field, with exposure to the magnetic field significantly enhancing nove l taste preference in male but not in female deer mice. Overall, our result s show that there are several sex differences in the behavior of deer mice, both in the characteristics of the CTA and in the response to magnetic fie ld exposure. The sex differences are discussed in terms of a sexually dimor phic sensitivity to experimental manipulation and the induction of stress a nd/or anxiety. (C) 2000 Elsevier Science Inc. All rights reserved.