The antinociceptive effect of stimulating the retrosplenial cortex in the rat tail-flick test but not in the formalin test involves the rostral anterior cingulate cortex.

The stimulation of the retrosplenial cortex (RSC) is antinociceptive in the rat tail-flick and formalin tests. The rat RSC is caudal to and send projections to the ipsilateral anterior cingulate cortex (ACC), which is also involved in pain processing. This study demonstrated that pre-treating the rostral (rACC), but not the caudal ACC with CoCl2 (1mM), or the rACC ablation increased the duration of the antinociceptive effect evoked by a 15-s period of electrical stimulation (AC, 60Hz, 20μA) of the RSC in the rat tail-flick.

The effect of intrathecal gabapentin on neuropathic pain is independent of the integrity of the dorsolateral funiculus in rats.

Aim: This study evaluates the contribution of inhibitory pain pathways that descend to the spinal cord through the dorsolateral funiculus (DLF) on the effect of intrathecal gabapentin against spinal nerve ligation (SNL)-induced behavioral hypersensitivity to mechanical stimulation in rats.

Main Method: Rats were submitted to a sham or complete ligation of the right L5 and L6 spinal nerves and a sham or complete DLF lesion. Next, the changes induced by intrathecal administration of gabapentin on the paw withdrawal threshold of rats to mechanical stimulation were evaluated electronically.

Stimulation of the occipital or retrosplenial cortex reduces incision pain in rats.

The electrical stimulation of the occipital (OC) or retrosplenial (RSC) cortex produces antinociception in the rat tail-flick and formalin tests. This study examined the antinociceptive effects of stimulating the OC or RSC in a rat model of post-incision pain. The involvement of the anterior pretectal nucleus (APtN) as intermediary for the effect of OC or RSC stimulation was also evaluated because the OC and RSC send inputs to the APtN, which is implicated in antinociception and nociception.

Stimulation-produced analgesia from the occipital or retrosplenial cortex of rats involves serotonergic and opioid mechanisms in the anterior pretectal nucleus.

Unlabelled: The electrical stimulation of the occipital (OC) or retrosplenial (RSC) cortex produces antinociception in the rat tail-flick test. These cortices send inputs to the anterior pretectal nucleus (APtN) which is implicated in antinociception and nociception. At least muscarinic cholinergic, opioid, and serotonergic mechanisms in the APtN are involved in stimulation-produced antinociception (SPA) from the nucleus.

Antinociceptive effect of stimulating the occipital or retrosplenial cortex in rats.

Unlabelled: A role for the occipital or retrosplenial cortex in nociceptive processing has not been demonstrated yet, but connections from these cortices to brain structures involved in descending pain-inhibitory mechanisms were already demonstrated. This study demonstrated that the electrical stimulation of the occipital or retrosplenial cortex produces antinociception in the rat tail-flick and formalin tests. Bilateral lesions of the dorsolateral funiculus abolished the effect of cortical stimulation in the tail-flick test.