The main finding of this study is that the vapocoolant spray was effective for increasing heat pain thresholds compared to saline spray (Fig. 1). Heat nociceptive thresholds increased by a mean 700 ms relative to baseline values reflecting a reduction in pain behavior sensitivity after application of the vapocoolant spray, whereas the increase in heat nociceptive thresholds was a mean of only 200 ms with the saline spray (Fig. 1). Compared to saline spray, vapocoolant spray produced a 29% increase in the mean heat pain threshold. Only 1 pup rat (1/20) in the vapocoolant group had no change in threshold