title: Changes in activity of spinal cells with muscular input in rats with referred muscular hyperalgesia from ureteral calculosis.
abstract: In rats with hyperalgesia of the obliquus externus muscle (OE) from artificial calculosis of the ipsilateral upper ureter, changes in cell activity were studied in the ipsilateral spinal cord (T11-T12) versus control animals. In cases of hyperalgesia of high degree, in the dorsal horn (0-900 microns) the following were found: significantly higher percentages of cells driven by OE stimulation (P < 0.03) and of spontaneously active cells with OE input (P < 0.02); significantly higher frequency of background discharge of cells with OE input (P < 0.002); among cells driven by OE stimulation, significantly higher percentages of neurons with exclusively deep input (P < 0.0006) and of neurons with low mechanical threshold of activation (P < 0.03). In the intermediate region of the cord (900-1600 microns), a significantly higher percentage was found of spontaneously active cells with OE input (P < 0.009) while in the ventral horn (1600-2300 microns) no changes were detected. The results indicate that referred muscle hyperalgesia of high degree is accompanied by a state of central sensitization probably triggered by the abnormal afferent input from the visceral focus.
authors.affiliation: Pathophysiology of Pain Laboratory, G. D. Annunzio University of Chieti, Italy.
authors.forename: M A
authors.initials: MA
authors.lastname: Giamberardino
authors.forename: A
authors.initials: A
authors.lastname: Dalal
authors.forename: R
authors.initials: R
authors.lastname: Valente
authors.forename: L
authors.initials: L
authors.lastname: Vecchiet
mesh_terms: D000200:Action Potentials; D000344:Afferent Pathways / Q000503:physiopathology; D000818:Animals; D004558:Electric Stimulation; D005260:Female; D006930:Hyperalgesia / Q000209:etiology / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000294:innervation*; D009431:Neural Conduction; D009475:Neurons, Afferent / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000503:physiopathology*; D014514:Ureteral Calculi / Q000503:physiopathology*; D014828:Vocalization, Animal