title: Exposure to extremely low-frequency magnetic field restores spinal cord injury-induced tonic pain and its related neurotransmitter concentration in the brain.
abstract: Spinal cord injury (SCI) is unequivocally reported to produce hyperalgesia to phasic stimuli, while both hyper- and hypoalgesia to tonic stimuli. The former is spinally mediated and the latter centrally. Besides, its management is unsatisfactory. We report the effect of magnetic field (MF; 17.96 μT, 50 Hz) on tonic pain behavior and related neurotransmitters in the brain of complete thoracic (T13) SCI rats at week 8. Adult male Wistar rats were divided into Sham, SCI and SCI+MF groups. Formalin-pain behavior was compared utilizing 5 min block pain rating (PR), 60 min session-PR, time spent in various categories of increasing pain (T0-T3) and flinch incidences. Serotonin (5-HT), dopamine (DA), norepinepherine (NE), gamma-aminobutyric acid (GABA), glutamate and glycine were estimated in brain tissue by liquid chromatography-mass spectrometry. Session-PR, block-PR and number of flinches were significantly lower, while time spent in categories 0-1 was higher in the SCI versus Sham group. These parameters were comparable in the SCI+MF versus Sham group. 5-HT concentration in cortex, remaining forebrain areas and brain stem (BS), was lower while GABA and NE were higher in BS of SCI, which were comparable with Sham in the SCI+MF group. The concentration of DA, glutamate and glycine was comparable amongst the groups. The data indicate significant hypoalgesia in formalin pain while increased in GABA, NE and decreased in 5-HT post-SCI, which were restored in the SCI+MF group. We suggest beneficial effect of chronic (2 h/day × 8 weeks) exposure to MF (50 Hz, 17.96 μT) on tonic pain that is mediated by 5-HT, GABA and NE in complete SCI rats.
authors: Department of Physiology, All India Institute of Medical Sciences , New Delhi , India.
authors: Suneel
authors: S
authors: Kumar
authors: Suman
authors: S
authors: Jain
authors: Thirumurthy
authors: T
authors: Velpandian
authors: Yury
authors: Y
authors: Petrovich Gerasimenko
authors: Valery
authors: V
authors: D Avelev
authors: Jitendra
authors: J
authors: Behari
authors: Madhuri
authors: M
authors: Behari
authors: Rashmi
authors: R
authors: Mathur
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D001921:Brain / Q000378:metabolism*; D008124:Locomotion; D055909:Magnetic Field Therapy; D008297:Male; D018377:Neurotransmitter Agents / Q000378:metabolism*; D010146:Pain / Q000209:etiology* / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D059408:Pain Management; D051381:Rats; D017208:Rats, Wistar; D013116:Spinal Cord / Q000473:pathology; D013119:Spinal Cord Injuries / Q000150:complications*
chemical_list: D018377:Neurotransmitter Agents