ANTINOCICEPTIVE EFFECTS OF PALATABLE SWEET INGESTA ON HUMAN RESPONSIVITY TO PRESSURE PAIN

Palatable sweet ingestion produces a morphine-like analgesia in both r ats and human infants (2-5). To determine whether palatable sweet inge sta induces antinociception in human adults, 60 university students (3 0 men, 30 women) were exposed to a pressure algometer both before and after consuming either a sweet soft drink, filtered tap water, or noth ing (Experiment 1). Pain responsivity was assessed with four pain meas ures: threshold, tolerance, and visual analogue scale (VAS) ratings of intensity and unpleasantness. Results showed that women who consumed either soft drink or water reported increased pain tolerance and VAS r atings at posttreatment compared with those receiving nothing. However , differences between groups were not found for men. Moreover, compare d to men, women reported lower pain thresholds and tolerances and rate d the pain as more intense. In Experiment 2, 40 women consumed either nothing or foods that they rated previously as palatable (chocolate-ch ip cookies), unpalatable (black olives), or neutral (rice cakes). Wome n who consumed the palatable sweet food showed increased pain toleranc e compared with those receiving the unpalatable food, the neutral food , or nothing. These data constitute the first demonstration that ''pal atability-induced antinociception'' (PIA) can occur in human adults. C opyright (C) 1997 Elsevier Science Inc.