Footshock produces analgesia but no gastrointestinal motility effects in the rat.

The effect of inescapable footshock was determined on gastrointestinal motility in unanesthetized rats. Inescapable footshock did not affect gastric emptying, small or large intestinal transit. Footshock produced a brief, naloxone-reversible thermal analgesia. These data indicate that gastrointestinal motility and analgesia are controlled by different central nervous system opioid mechanisms.