Effect Of Neuroactive Peptide Urocortin Ⅱ On Rat Striatum Neuron’s Spontaneous Discharge And It’s Mechanism

ObjectiveThe study investigated the effects of neuropeptide urocortinⅡ (UCNⅡ)on striatum (STR) neuron’s for a further comprehension of the pathogenesis ofParkinson’s disease (PD).MethodsThe experiment used60Sprague-Dawley (SD) rats, and seven pipemicroiontophoresis was used to observe the effects of UCNⅡ on STRneuron’s spontaneous discharge in SD and PD model rats, also observed theeffects of UCNⅡ whether had intensity-dependence. In addition,micro-electrophoresis corticotrophin regulating factor receptor2(CRF2)blocker—astressin (AST), and observed the effects on UCNⅡ on GLU’s STRneurons in SD and PD model rats. Micro-electrophoresis were recorded beforeand after neuron discharge frequency, micro-electrophoresis drugs dischargefrequency variation=(electrophoresis drugs during discharge frequency–before the electrophoresis and20s discharge frequency)/electrophoresis frontand20s discharge frequency x100%, slightly electrophoresis drugs dischargechange more than±30%for effective critical value. ResultsUCNⅡ could inhibit the firing rate of84%(49/58) STR neuron’sspontaneous discharge, the neuronal average firing rates decreased from(6.98±1.05) Hz to (3.93±1.02Hz)(P<0.01), and its inhibitory effects followedintensity-dependence (r=0.91). After addition of the UCNⅡ inhibitor-AST, thespontaneous firing rates were enhanced in78%(41/52) tested STR neurons,the neuronal firing rates increased from (5.49±1.08) Hz to (8.01±1.13) Hz (P<0.01). Further, during the micro-electrophoresis of GLU, the excitatory firingof STR neurons was also attenuated by addition of UCNⅡ while ASTapplication could enhance the excitation. In addition, UCNⅡ could inhibit thePD of STR neuron’s spontaneous discharge，the neuronal average firing ratesdecreased from (12.37±2.58) Hz to (8.28±1.02) Hz (P<0.01).Conclusion1. UCNⅡ can inhibit SD and PD rats of STR spontaneous discharge ofneurons, and its inhibitory effects followed intensity-dependence.2. UCNⅡ can affect the GLU neurotransmitter in SD and PD pathologicalcases of STR neurons.3. UCNⅡ played inhibitory effects on STR neurotransmitters via CRF2receptor and protect of nervous system diseases.