Analgesic Action Sites of Pregabalin by fMRI of Spinal Cord & Brain in Anesthetized Rats & Its Qualification Against Behavioral Assay in Awake Rats

Fuqiang Zhao¹, Denise Welsh¹, Mangay Williams¹, Hongyu Annie Liang², Alexandre Coimbra¹, Mark O. Urban², Mark Bowlby², Richard Hargreaves², Jeffrey L. Evelhoch¹, Donald S. Williams¹

Pregabalin (Lyrica) is used for the treatments of epilepsy and pain. Both its anatomical targets and its mechanism of action are poorly understood. In this study, the suppression effects of pregabalin on noxious electrical stimulation (NES) induced responses were investigated by BV fMRI in anesthetized rats, and by behavioral assay (vocalization) in awake rats. Our fMRI and behavioral results suggest that 1) pregabalin has efficacy on NES-induced pain in nave rats; and 2) the analgesic action sites of pregabalin are not in the primary somatosensory pathway (spinal cord, dorsal column nuclei, thalamic relay, S1), but in other activated regions.