The opioid receptor antagonist, naloxone, enhances ocular motor compensation in guinea pig following peripheral vestibular deafferentation.
The opioid receptor antagonist, naloxone, has been demonstrated to enhance recovery from spinal cord injury and fluid percussion brain injury. The present study investigated, for the first time, the effects of naloxone on behavioral recovery following unilateral peripheral vestibular deafferentation (unilateral labyrinthectomy, UL) in guinea pig. An ip injection of 5 mg/kg naloxone 30 min pre-UL and 5 h post-UL was found to significantly reduce the frequency of spontaneous nystagmus relative to the vehicle control group (P < 0.005). However, a lower dose (2.5 mg/kg) had no effect. At either dose, the effects on the postural symptoms, yaw head tilt and roll head tilt, were small by comparison and in most cases nonsignificant. These results suggest that naloxone can reduce the ocular motor effects of UL in a dose-dependent fashion.
Dutia
M B
MB
Department of Physiology, University of Edinburgh Medical School, United Kingdom.
Gilchrist
D P
DP
Sansom
A J
AJ
Smith
P F
PF
Darlington
C L
CL
D000222:Adaptation, Physiological / Q000187:drug effects*; D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D003714:Denervation; D004305:Dose-Response Relationship, Drug; D005260:Female; D006168:Guinea Pigs; D007274:Injections, Intraperitoneal; D008297:Male; D009270:Naloxone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D009760:Nystagmus, Physiologic / Q000187:drug effects; D009801:Oculomotor Muscles / Q000187:drug effects / Q000502:physiology*; D014722:Vestibule, Labyrinth / Q000294:innervation* / Q000601:surgery
D009292:Narcotic Antagonists; D009270:Naloxone