Papers of the Week

Descending control from supraspinal neuronal networks onto spinal cord neurons can modulate nociceptionEndogenous opioids in these brain circuits participate in pain modulationA differential opioidergic role for brain nuclei involved in supraspinal pain modulation has not been previously reported WHAT THIS ARTICLE TELLS US THAT IS NEW: In vivo electrophysiologic recordings from the dorsal horn of the spinal cord in male rats reveal differential effects of morphine at the anterior cingulate cortex, right amygdala, and the ventromedial medulla on evoked pain responsesThese data differentiate supraspinal opioid circuit regulation of spinal nociceptive processing and suggest that the regulation of sensory and affective components of pain are likely separate BACKGROUND:: The anterior cingulate cortex and central nucleus of the amygdala connect widely with brainstem nuclei involved in descending modulation, including the rostral ventromedial medulla. Endogenous opioids in these circuits participate in pain modulation. The hypothesis was that a differential opioidergic role for the brain nuclei listed in regulation of spinal neuronal responses because separable effects on pain behaviors in awake animals were previously observed.