title: Evaluation of antinociceptive and neurotoxic effects of intrathecal dexmedetomidine in rats.
abstract: OBJECTIVE
  Dexmedetomidine has been reported to produce analgesia after intrathecal administration. In the present study the α2-adrenoceptor agonist dexmedetomidine was evaluated for its potential spinal neurotoxic effects.
  
  
  METHODS
  Three days after intrathecal cannulation, rats were administered either dexmedetomidine (3 μg/30 μL, i.t.) or saline (30 μL, i.t.). Antinociceptive, sedative and motor effects of intrathecal administrations of dexmedetomidine or saline were evaluated during 90 min. The tail-flick and hot plate tests were used to assess the thermal nociceptive threshold. Seven days after drug administration, animals were sacrified and spinal cords were evaluated for histopathological changes by light microscopy.
  
  
  RESULTS
  Dexmedetomidine administered intrathecally produced antinociception. Antinociception was accompanied by immediate sedation and loss of placing-stepping reflexes that lasted over 40 min in all dexmedetomidine administered rats. In all rats, microscopic examination revealed mild gliosis and minimal infiltration of inflamatory r cells in posterior white matter. Mild (total score 4-6) histopathologic lesions were seen in four animals in dexmedetomidine adminisered rats, but there was no statistically significant difference when compared with the saline administered rats.
  
  
  CONCLUSIONS
  We observed that intrathecal injections of dexmedetomidine at the dose of 3 μg/30 μL produce antinociception but did not cause any histopathological sign of injury in the spinal cord.
authors.affiliation: Department of Anesthesiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey.
authors.forename: Ozgü
authors.initials: O
authors.lastname: Işgüzar
authors.affiliation: Department of Anesthesiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey.
authors.forename: Sibel
authors.initials: S
authors.lastname: Barış
authors.affiliation: Department of Physiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey.
authors.forename: Ayhan
authors.initials: A
authors.lastname: Bozkurt
authors.affiliation: Department of Pathology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey.
authors.forename: Bilge
authors.initials: B
authors.lastname: Can
authors.affiliation: Department of Pharmacology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey.
authors.forename: Sırrı
authors.initials: S
authors.lastname: Bilge
authors.affiliation: Department of Anesthesiology, Faculty of Medicine, Ondokuz Mayıs University, Samsun, Turkey.
authors.forename: Hatice
authors.initials: H
authors.lastname: Türe
keywords: Dexmedetomidine; histopathology; intrathecal; neurotoxicity; rat