Different role of spinal 5-HT(hydroxytryptamine)7 receptors and descending serotonergic modulation in inflammatory pain induced in formalin and carrageenan rat models

Spinal 5-HT7R plays a significant inhibitory role in descending serotonergic modulation in pain induced by formalin but not carrageenan. Descending serotonergic modulation is differentially involved in inflammatory pain induced by formalin and carrageenan, with facilitatory and inhibitory effects, respectively.