Suppression of drinking by exposure to a high-strength static magnetic field.

High-strength static magnetic fields of 7 T and above have been shown to have both immediate and delayed effects on rodents, such as the induction of locomotor circling and the acquisition of conditioned taste aversions. In this study, the acute effects of magnet field exposure on drinking were examined. Exposure to a 14.1-T magnetic field for as little as 5 min significantly decreased the amount of a glucose and saccharin solution (G+S) consumed by water-deprived rats over 10 min. The decreased intake could be accounted for largely, but not entirely, by an increase in the latency of magnet-exposed rats to initiate drinking. When intake was measured for 10-60 min after the initiation of drinking, thus controlling for increased latency, magnet-exposed rats still consumed less G+S than sham-exposed rats. The increased latency was not due simply to an inability of magnet-exposed rats to reach the elevated sipper tube of the G+S bottle, providing rats with long tubes that could be reached without raising their heads normalized intake but latency was still increased. The increased latency and decreased intake appeared to be secondary to somatic effects of magnet exposure, however, because during intraoral infusions magnet-exposed rats consumed the same amount of G+S with the same latency to reject as sham-exposed rats. The suppression of drinking by magnetic field exposure is consistent with the acute effects of other aversive stimuli, such as whole-body rotation, on short-term ingestion. These results add to the evidence that high-static strength magnetic fields can have behavioral effects on rodents.