RESPONSES TO COLD, HEAT, AND PAIN INCREASE LOCOMOTION IN RATS AND AREATTENUATED BY PINEALECTOMY

Responses to cold, heat, and pain increase locomotion in rats and are attenuated by pinealectomy. PHYSIOL BEHAV 55(3) 583-586, 1994.-The eff ects of pinealectomy on locomotor behavior responses to cold, heat or pain were assessed in freely moving rats. External cold (4 degrees C) or heat (36 degrees C) stress produced increases of locomotion (includ ing horizontal and vertical movement, and total distance traveled), in creases of number of turnings (including both clockwise and counterclo ckwise), and decreases of postural freezing in rats. In addition, pain (produced by intradermal injection of normal saline) was also shown t o produce increases of locomotion (including horizontal and vertical m ovement, and total distance traveled) and decreases of postural freezi ng in rats. The increases of locomotion (including horizontal and vert ical movement, and total distance traveled), as well as the decreases of postural freezing induced by either cold or pain, were attenuated b y pretreatment of animals with pinealectomy. The heat-induced increase s of vertical movement as well as the decreases of postural freezing w ere also attenuated by pinealectomy. The results indicate that these n onphotic, stress-provoking stimuli act through the pineal gland to ind uce escape behaviors to try to get out of the stressed conditions in r ats.