Supraspinal-selective TRPV1 desensitization induced by intracerebroventricular treatment with resiniferatoxin.

The transient receptor potential vanilloid type 1 (TRPV1) is a thermosensitive cation channel that triggers heat pain in the periphery. Long-term desensitization of TRPV1, which can be induced by excess amounts of agonists, has been a method for investigating the physiological relevance of TRPV1-containing neuronal circuits, and desensitization induced by various routes of administration, including systemic, intrathecal and intraganglionic, has been demonstrated in rodents. In the present study, we examined the effect of intracerebroventricular (i.

Serotonergic System Does Not Contribute to the Hypothermic Action of Acetaminophen.

Acetaminophen (AcAP), a widely-used antipyretic and analgesic drug, has been considered to exert its effects via central mechanisms, and many studies have demonstrated that the analgesic action of AcAP involves activation of the serotonergic system. Although the serotonergic system also plays an important role in thermoregulation, the contribution of serotonergic activity to the hypothermic effect of AcAP has remained unclear. In the present study, we examined whether the serotonergic system is involved in AcAP-induced hypothermia.