Melatonin replacement nullifies the effect of light-induced functional pinealectomy on nociceptive rhythm in the rat

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Laurie Wideman, Safrit-Ennis Distinguished Professor (Creator)
The University of North Carolina at Greensboro (UNCG )
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Abstract: Rats maintained on a 12 h daily photoperiod (12:12 LD cycle), exhibited a diunal variation in sensitivity to both heat-elicited and pressure-elicited pain, with low sensitivity at 2 h before the end of the scotophase and higher at 4 h after the onset of photophase. Functional pinealectomy induced by a single LL day effaced the baseline diurnal rhythm of sensitivity to pressure-elicited pain, and reversed that to heat-elicited pain. Oral administration of physiological doses of melatonin into functionally pinealectomized rats, nullified the effect of functional pinealectomy, restoring the normal baseline rhythms of both pressure-elicited and heat-elicited nociceptive responses. The role of melatonin in modulating nociception is discussed in light of an indoleaminergic-opioid system.

Additional Information

Physiology & Behavior 55(4): 735- 739
Language: English
Date: 1994
Melatonin, Nociception, Diurnal rhythm, Functional pinealectomy

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