title: Cortical stimulation and tooth pulp evoked potentials in rats: a model of direct anti-nociception.
abstract: While the effect of cortex stimulation on pain control is widely accepted, its physiological basis remains poorly understood. We chose an animal model of pain to study the influence of sensorimotor cortex stimulation on tooth pulp stimulation evoked potentials (TPEPs). Fifteen awake rats implanted with tooth pulp, cerebral cortex, and digastric muscle electrodes were divided into three groups, receiving 60 Hz, 40 Hz and no cortical stimulation, respectively. TPEPs were recorded before, one, three and five hours after continuous stimulation. We observed an inverse relationship between TPEP amplitude and latency with increasing tooth pulp stimulation. The amplitudes of the early components of TPEPs increased and their latency decreased with increasing tooth pulp stimulation intensity. Cortical stimulation decreased the amplitude of TPEPs; however, neither the latencies of TPEPs nor the jaw-opening reflex were changed after cortical stimulation. The decrease in amplitude of TPEPs after cortical stimulation may reflect its anti-nociceptive effect.
authors.affiliation: Department of Normal, Pathological and Clinical Physiology, 3rd Faculty of Medicine, Charles University, Prague, Czech Republic. robert.rusina@ftn.cz.
authors.forename: Robert
authors.initials: R
authors.lastname: Rusina
authors.forename: Stephane
authors.initials: S
authors.lastname: Barek
authors.forename: Simon
authors.initials: S
authors.lastname: Vaculin
authors.forename: Jean
authors.initials: J
authors.lastname: Azérad
authors.forename: Richard
authors.initials: R
authors.lastname: Rokyta
mesh_terms: D000818:Animals; D055592:Biophysical Phenomena; D003782:Dental Pulp / Q000294:innervation* / Q000502:physiology; D004195:Disease Models, Animal; D004558:Electric Stimulation / Q000379:methods*; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D007568:Jaw / Q000503:physiopathology; D008297:Male; D010146:Pain / Q000503:physiopathology*; D059408:Pain Management; D010147:Pain Measurement; D051381:Rats; D017207:Rats, Sprague-Dawley; D012018:Reflex / Q000502:physiology; D013003:Somatosensory Cortex / Q000502:physiology*; D013997:Time Factors