Mechanisms underlying antinociception provoked by heterosegmental noxious stimulation in the rat tail-flick test

Physiological studies were conducted to examine the effects of noxious stimulation of one hindpaw or one forepaw on the latency of the withdrawal reflex in the tail-flick test in lightly anesthetized spinally intact or transected rats. Male Sprague-Dawley rats were anesthetized with an intraperitoneal injection of a mixture of Na-pentobarbital (20 mg/kg) and chloral hydrate (120 mg/kg). After baseline readings were taken in the tail-flick test, …