Distinct modulation of evoked and spontaneous EPSCs by purinoceptors in the nucleus tractus solitarii of the rat

• DOI: 10.1111/j.1469-7793.2001.0469k.x
• Publication Date: 2004-08-05T11:13:24Z
• Authors: Fusao Kato; Eiji Shigetomi
• Keywords: PPADS; Solitary tract; Adenosine triphosphate; Adenosine A1 receptor

Whole-cell transmembrane currents of second-order neurones in the caudal part nucleus tractus solitarii (cNTS) brainstem slices rat were recorded to analyse effects adenosine 5'-triphosphate (ATP) on: (1) EPSCs evoked by solitary tract stimulation (eEPSCs) and (2) spontaneous (sEPSCs). ATP (10-6 10-4 m) significantly reduced amplitude eEPSCs 46.6 +/- 7.4 % increased frequency sEPSCs 268.0 71.5 control without significant changes sEPSC amplitude. These opposite on concurrently observed about 80 cNTS recorded. The reduction eEPSC was similarly with addition an equimolar solution but not alpha,beta-methylene suppressed 8-cyclopentyltheophylline (CPT) 8-cyclopentyl-1,3-dipropylxanthine (DPCPX). Addition pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid (PPADS) did affect ATP. increase remained under tetrodotoxin abolished presence PPADS. It is suggested that activates: presynaptic A1 receptors, after being hydrolysed adenosine, reducing release glutamate from primary afferent terminals P2X receptors axon intrinsic excitatory facilitating glutamate. This first evidence modulates synaptic inputs arising distinct origins converging a single postsynaptic neurone diametrically directions through activation purinoceptors.