title: Hypoalgesia in mice lacking aquaporin-4 water channels.
abstract: Previous studies have demonstrated the involvement of astrocytes in the modulation of pain. The water channel aquaporin-4, which is expressed in astrocytes but not neurons, has also been demonstrated to function in sensory processing, including hearing, vision, and olfaction. In the present study, we investigated a possible role of aquaporin-4 in the processing of nociception by measuring behavioral responses to noxious stimulation in aquaporin-4 knockout mice. Pain thresholds were increased in knockout mice, when compared to wild-type mice, with thermal and chemical stimulation but not mechanical stimulation. Aquaporin-4 knockout mice presented normal locomotor activity and basal skin temperature. Likewise, the electrophysiological recordings showed a significant decrease in the number of dorsal horn neurons sensitive to noxious thermal stimuli in aquaporin-4 knockout mice. Moreover, latencies to thermal stimuli were significantly prolonged in a subset of dorsal horn wide-dynamic-range neurons. Taken together, these results suggest that aquaporin-4 plays a role in the processing of nociception.
authors.affiliation: Institute of Neurobiology, Institutes of Brain Science and State Key Laboratory of Medical Neurobiology, Fudan University, 138 Yi-Xue-Yuan Road, Shanghai 200032, PR China.
authors.forename: Feng
authors.initials: F
authors.lastname: Bao
authors.forename: Mengling
authors.initials: M
authors.lastname: Chen
authors.forename: Yuqiu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhiqi
authors.initials: Z
authors.lastname: Zhao
mesh_terms: D000200:Action Potentials / Q000235:genetics; D000818:Animals; D051401:Aquaporin 4 / Q000172:deficiency*; D001522:Behavior, Animal; D019417:Hindlimb Suspension / Q000379:methods; D006358:Hot Temperature / Q000009:adverse effects; D006930:Hyperalgesia / Q000235:genetics* / Q000503:physiopathology; D051379:Mice; D018345:Mice, Knockout; D009474:Neurons / Q000502:physiology; D010147:Pain Measurement / Q000379:methods; D017288:Pain Threshold / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D045442:Rotarod Performance Test / Q000379:methods; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism
chemical_list: C496031:Aqp4 protein, mouse; D051401:Aquaporin 4