We present a protocol to measure [14C]-iodoantipyrine (IAP) uptake and assess the activation of neural substrates that are involved in central post-stroke pain (CPSP) in a rodent model.
Approximately 8% of stroke patients present symptoms of central post-stroke pain (CPSP). CPSP is associated with allodynia and hypersensitivity to nociceptive stimuli. Although some studies have shown that neuropathic pain may involve the dorsolateral prefrontal cortex, rostral anterior cingulate cortex, amygdala, hippocampus, periaqueductal gray, rostral ventromedial medulla, and medial thalamus, the neural substrates and their connections that mediate CPSP remain unclear. [14C]-Iodoantipyrine (IAP) uptake can be measured to evaluate spontaneously active pain. It can be used to assess the activation of neural substrates that may be involved in CPSP in an animal model. The [14C]-IAP method in rats is less expensive to perform compared with other brain mapping techniques. The present [14C]-IAP protocol is used to measure the activation of neural substrates that are involved in CPSP that is induced by lesions of the ventral basal nucleus (VB) of the thalamus in a rodent model.
Slag blødning har vist seg å forekomme i mer enn 8% av pasientene som lider av nevropatisk smerte, referert til som sentral etter-slag smerte (CPSP). 1-3 CPSP kan resultere fra somatosensory dysfunksjon, for derved å indusere overfølsomhet og allodyni. 4 men de patofysiologiske mekanismer for somatosensoriske dysfunksjon i CPSP fortsatt usikre. For eksempel tap av somatiske fornemmelser resulterer fra neuronal deafferentation i hemoragisk hjerneområde. Hyperalgesi kan være forårsaket av hyperexcitability av sentrale nociceptive neuroner eller sentral disinhibition, 5, 6, men de nevrale underlag som er involvert i CPSP symptomene forblir ukjent. Noen studier har antydet at dorsolateral prefrontal cortex (dPFC), rostralt anterior cingulate cortex (ACC), amygdala, hippocampus, periaqueductal grå (PAG), rostralt ventromediale medulla, og deres forbindelser med hverandre megle nociceptive behandling. 7 Tilleggsly, medial prefrontal cortex (MPFC) -amygdala kretser ble vist å være involvert i smerte-relaterte oppfatning. 8 Data om de patofysiologiske mekanismer CPSP er mangfoldig, og aktivering av nerve underlag i CPSP trenger ytterligere gransking.
[14 C] -Iodoantipyrine (IAP) opptak blir brukt til indirekte observere regional cerebral blodstrøm (rCBF), forutsatt en sammenheng mellom hjerneaktivitet og CBF. Selv [14 C] -IAP kan ikke vurdere hjernens aktivitet i sanntid, slik som med funksjonell magnetisk resonans imaging (fMRI), den har flere fordeler. For eksempel, [14C] -IAP er egnet for måling av spontant forekommende hjerne hendelser i løpet av patologiske tilstander. 9 Videre, [14C] -IAP opptaket målt uten bedøvelse. Det koster også mindre enn andre bildemetoder, inkludert fMRI og positronemisjonstomografi (PET). Den [14 C] -IAP metoden har blitt foreslått å være passende for measuring spontan smerte (f.eks CPSP) som er indusert ved lesjoner i den ventrale basal kjernen (VB) i thalamus. 9
Den nåværende protokollen beskriver hvordan du utfører [14 C] -IAP metode for å vurdere involvering av nevrale substrat for CPSP som er forårsaket av lesjoner i VB i thalamus i en dyremodell. Teknikken gir en måte å bestemme de patofysiologiske mekanismene som ligger til grunn CPSP symptomer på atferdsmessige og nevrale nivå.
I atferdstester, den CPSP gruppen viste reduksjoner av pote uttak terskel i den termiske smerte test og mekanisk kraft i von Frey testen ved baseline og uker 1 -. 5. Funnene var i samsvar med en tidligere studie 14
Den [14C] -IAP metoden er avhengig av pikselintensiteten fra hjernen bilder for kvantitativ analyse av forskjellige hjerneskiver. For å evaluere dataene i hjernen bilder, ble det pikselsignalintensiteten definert. I denne studien ble miljøbakgrunnssignal de…
The authors have nothing to disclose.
Denne studien ble støttet av National Science Council tilskudd til Dr. Bai-Chuang Shyu (NSC 99-2320-B-001-016-My3, NSC 100-2311-B-001-003-My3, og NSC 102-2320- B-001-026-My3). Dette arbeidet ble utført ved Institute of Biomedical Sciences, som fikk støtte fra Academia Sinica.
Anesthetic: | |||
Isoflurane | Halocarbon Products Corporation | NDC 12164-002-25 | 4% |
Surgery | |||
homeothermic blanket system | Harvard Apparatus | Model 50–7079 | body temperature were maintained at 36.5-37.5°C. |
10µl micro syringe | Hamilton | 80008, Model 1701SN | injected with collagenase |
polyethylene-50 tubing | Becton, Dickinson and Company | 427411 | catheterized into external jugular vein |
1 c.c syringe | Terumo Medical Products | SS-01T | injected with 14C-IAP and saline. |
saline (Sodium Chloride 0.9gm) | Taiwan Biotech Co., LTD. | 100-130-0201 | To flush the tube |
Drugs: | |||
type 4 collagenase | Sigma | C5138-500MG | 0.125 U |
Gentamicin | Sigma | G1264-250MG | 6 mg/kg |
Heparin | Sigma | H9399 | 20 U/ml; 0.1 ml/day |
14C-iodoantipyrine (IAP) | PerkinElmer | NEC712 | 125 mCi/kg in 300 ml of 0.9% saline |
Potassium chloride | Merck | 1.04936.1000 | 3 M |
Behavior system: | |||
von Frey esthesiometer | Fabrication Enterprises, Inc. | Baseline Tactile Monofilaments 12-1666 | mechanical hyperalgesia was assessed by measuring the withdrawal response to a mechanical stimulus |
plantar test apparatus | IITC Life Science | IITC 390G Plantar Test | Thermal hyperalgesia was assessed by measuring the hind paw withdrawal latency in response to radiant heat. |
Brain slice: | |||
Optimal Cutting Temperature compound | Sakura Fintek Inc | 4583 | embedded the brain |
dry ice | frozen in dry ice/methylbutane (approximately −55°C) | ||
methylbutane | Sigma | M32631-1L | frozen in dry ice/methylbutane (approximately −55°C) |
Cryostat | Leica Biosystems Nussloch GmbH, Germany | Leica CM1850 | Coronal brain slice were sectioned on this machine. |
Data analyze | |||
exposure cassettes with a phosphor screen | Amersham Biosciences | 20 cm x 25 cm | The slices were dried on glass slides and placed alongside five standard filter papers with graded radioactivity. All of the slides were exposed to the cassettes at −20°C. |
γ-counter | Beckman Coulter | Beckman LS 6500 Liquid Scintillation Counter | To measure the radioactivity count of the filter papers. |
Typhoon 9410 Variable Mode Imager | GMI, Inc. | WS-S9410 | To read phosphor screen which was exposed by brain slice |
Statistical Parametric Mapping (SPM) | Wellcome Centre for Neuroimaging | version 8 | all of the brains were averaged to create the final brain template. To determine significant differences between the images in these two groups, the images were derived by subtracting the sham group from the CPSP group. |
ImageJ | http://imagej.nih.gov/ij | version 1.46 | Adjacent sections were aligned both manually and using Stack- Reg, an automated pixel-based registration algorithm in ImageJ software. All of the original three-dimensionally reconstructed brains were smoothed and normalized to the reference rat brain model. |
Matlab | MathWorks | version 2009b | used Pearson correlation coefficients to examine the relationships between the CPSP and sham groups. An inter-regional correlation matrix was calculated across animals from each group. |
Pajek | http://Pajek.imfm.si/ | version 3.06 | Graphical theoretical analysis was performed on networks defined by the above correlation matrices using Pajek software. |