A study of different structures of central nervous system implicated in Parkinson’s disease neuropathic pain

Abstract

Pain is the major non-motor symptom in Parkinson’s disease (PD). Its mechanism is still poorly understood although an increase in excitation or a decrease in inhibition have been reported in preclinical studies. These studies have mostly investigated mechanical pain by considering the decrease in a nociceptive threshold. Only a few studies have focused on thermal pain in animal models of PD. Besides, fluorescence tracers have been widely used to label projecting neurons, but the linkage between the susbtantia nigra and the spinal pain process hasn’t yet been demonstrated thoroughly. Therefore, the goal of this study was to assess the thermal nociceptive behavior of rats subjected to 6- hydroxydopamine (6-OHDA) administration, which constitutes an animal model of PD. Also, to investigate inhibitory and excitatory markers in the 6-hydroxydopamine (6-OHDA) PD rat model. Therefore, the expression of three inhibitory markers parvalbumin, glutamate decarboxylase 67 (GAD67) and vesicular GABA transporter (VGAT) was evaluated in bilateral 6-OHDA lesioned rat. Besides, GFAP, Serine Racemase and Pannexins were studied. In addition, Fluororuby (FR) has been injected in the substantia nigra pars compacta to assess its anterograde