Evaluation of thermal preference behavior in the rat model of rotenone induced hemi-Parkinson using double plate technique

Background and Aim : Parkinson’s disease is characterized primarily as a neurodegenerative disorder that leads to disabling motor and cognitive impairment. Pain is an important and distressing symptom in Parkinson’s disease (PD). The present study aimed to investigate rotenone induced substantia nigral lesion effect on cold aversion behavior in the rat using double plate technique.Methods : Adult male Wistar rats were used in this study. For induction of hemi-Parkinson model, rotenone (12 μg/site in 1μl, DMSO) was injected directly into the substantia nigra pars compacta (SNc) using stereotaxic apparatus in the following coordination (AP: 5.0 mm; L: 2.0 mm; DV: 8.0 mm). The double plate device comprised two metal plates with different temperature (thermo-neutral plate: 24 ºC and cool plate: 14 ºC) and a Plexiglas cage was placed on the two plates. The device was equipped with a digital video tracking system. 7 and 14 days after Parkinson induction double plate test was performed and the behavioral parameters include speed and the time spent on cool or thermo-neutral plate were analyzed for a period of 10 minutes.Results : 7 and 14 days following surgery, control animals moved on both plates with the approximately similar speed and spent near to equal time on both plates. The time spends on the innocuous cold plate significantly decreased (P <0.05) in hemi-Parkinsonian animals in comparison with sham control animals.Conclusion : According to this finding hemi-Parkinsonian rats preferred thermo-neutral plate to stay and avoided from cool plate during the test as the result of central neuropathy induced cold allodynia.

Keywords:

Parkinson , Rotenone , Double-plate , Allodynia , Rat