title: Investigation of the functional difference between the pathological itching and neuropathic pain-induced rat brain using manganese-enhanced MRI.
abstract: BACKGROUND
  There is a remarkable similarity in the central sensitization of itch and pain. However, the interactions between itch and pain are only partially understood.
  
  
  OBJECTIVE
  To investigate the functional activity of cerebral regions to provide clear information on the neuronal pathways related to both pathological itching (PI) and neuropathic pain (NP).
  
  
  METHODS
  Sprague-Dawley rats were used in this study. PI was induced via neonatal capsaicin treatment, and scratching behavior was counted. NP was induced via lumbar spinal nerve 5 (L5) ligation, and mechanical allodynia was measured. The activated cerebral regions in the control, PI, and NP rats were measured using a 4.7 T magnetic resonance imaging (MRI) system and manganese-enhanced MRI (MEMRI). Subsequently, the cerebral activation regions were identified, and the signal intensity was compared.
  
  
  RESULTS
  Cerebral activities of the PI-induced rats were found in three regions -7.10 and -4.20 mm, and two regions -2.45 mm from the bregma. In the NP-induced rats, cerebral activities were found in two regions 7.10 and -2.45 mm, and one region -4.20 mm from the bregma. Comparing the PI and NP rats, the cerebral activities were different in one region -7.10 mm and -2.45 mm, and two regions -4.20 mm from the bregma. The different regions were the midbrain area, the geniculate complex, the hypothalamic area, and the amygdala area.
  
  
  CONCLUSIONS
  Our MEMRI investigation indicates functionally different activity of cerebral regions due to the effect of PI or NP. These findings provide clear information of the signal transduction in the brain regarding PI or NP that share a similar neuronal pathway.
authors.affiliation: Gachon Institute of Pharmaceutical Science, Gachon University, Incheon, Republic of Korea.
authors.forename: Keun-Yeong
authors.initials: KY
authors.lastname: Jeong
authors.affiliation: Gachon Institute of Pharmaceutical Science, Gachon University, Incheon, Republic of Korea.
authors.forename: Hwan Mook
authors.initials: HM
authors.lastname: Kim
authors.affiliation: Department of Biomedical Laboratory Science, College of Health and Medical Science, Daejeon University, Daejeon, Republic of Korea shigella@naver.com.
authors.forename: Ji-Hyuk
authors.initials: JH
authors.lastname: Kang
mesh_terms: D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology*; D002712:Chlorides / Q000737:chemistry; D003287:Contrast Media / Q000737:chemistry; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D017895:Manganese Compounds / Q000737:chemistry; D009437:Neuralgia / Q000473:pathology*; D011537:Pruritus / Q000473:pathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction
chemical_list: D002712:Chlorides; D003287:Contrast Media; D017895:Manganese Compounds; C025340:manganese chloride
keywords: Brain; functional activity; manganese-enhanced magnetic resonance imaging (MEMRI); neuropathic pain; pathological itching; rat