Adenosine A1 receptor stimulation reduces D1 receptor-mediated GABAergic transmission from striato-nigral terminals and attenuates l-DOPA-induced dyskinesia in dopamine-denervated mice.

Adenosine A1 receptor stimulation reduces D1 receptor-mediated GABAergic transmission from striato-nigral terminals and attenuates l-DOPA-induced dyskinesia in dopamine-denervated mice. Exp Neurol. 2014 Aug 27; Authors: Mango D, Bonito-Oliva A, Ledonne A, Cappellacci L, Petrelli R, Nisticò R, Berretta N, Fisone G, Mercuri NB Abstract γ-Aminobutyric acid A receptor (GABAAR)-mediated postsynaptic currents were recorded in brain slices from substantia nigra pars reticulate neurons. The selective adenosine A1 receptor (A1R) antagonist, 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), increased the frequency, but not the amplitude of spontaneous inhibitory post-synaptic currents (IPSCs) in the presence of the dopamine D1 receptor agonist SKF 38393 (SKF) and phosphodiesterase 10A inhibitors (papaverine or AE90074). Under these conditions, DPCPX also increased the amplitude of evoked IPSCs (eIPSCs). The effect of DPCPX was also examined in a mouse model of Parkinson's disease (PD), generated by unilateral denervation of the dopaminergic input to the striatum. In this model, SKF alone was sufficient to increase sIPSC frequency and eIPSC amplitude, and these effects were not potentiated by DPCPX. To confirm a depressive effect of A1Rs on the synaptic release of GABA we used the selective A1R agonist 5'-chloro-5'-deoxy-N(6)-(±)-(endo-norborn-2-yl)adenosine (5'Cl5'd-(±)-ENBA) which has limited peripheral actions. We found that 5'Cl5'd-(±)-ENBA ...
Source: Experimental Neurology - Category: Neurology Authors: Tags: Exp Neurol Source Type: research