title: Influence of parafascicular thalamic input on neuronal activity within the nucleus accumbens is mediated by nitric oxide - an in vivo study.
abstract: OBJECTIVE
  Thalamostriatal fibers are involved in cognitive tasks such as acquisition, learning, processing of sensory events, and behavioral flexibility and might play a role in Parkinson's disease. The aim of the present study was the in vivo electrochemical characterization of the projection from the lateral aspect of the parafascicular thalamus (Pfl) to the dorsolateral aspect of the nucleus accumbens (dNAc). Since nitric oxide (NO) plays a crucial role in striatal synaptic transmission, its implication in Pfl-evoked signaling within the dNAc was investigated.
  
  
  METHODS
  The Pfl was electrically stimulated utilizing paired pulses and extracellular potentials were recorded within the dNAc. Simultaneously, the dNAc was superfused using the push-pull superfusion technique for local application of compounds and for assessing the influence of NO on release of glutamate, aspartate and GABA.
  
  
  RESULTS
  Stimulation of the Pfl evoked a negative-going component at 9-14 ms followed by a positive-going component at 39-48 ms. The early response was current-dependent and diminished by superfusion of the dNAc with tetrodotoxin, kynurenic acid or N(G)-nitro-l-arginine methyl ester (L-NAME), while 3-(2-hydroxy-2-nitroso-1-propylhydrazino)-1-propanamine (PAPA/NO) increased this evoked potential. Transmitter release was inhibited by L-NAME and facilitated by PAPA/NO.
  
  
  CONCLUSIONS
  This study describes for the first time in vivo extracellular electrical responses of the dNAc on stimulation of the Pfl. Synaptic transmission within the dNAc on stimulation of the Pfl seems to be facilitated by NO.
authors.affiliation: Department of Pharmacology and Toxicology, University of Innsbruck, Peter-Mayr-Strasse 1, A-6020 Innsbruck, Austria.
authors.forename: Michaela M
authors.initials: MM
authors.lastname: Kraus
authors.affiliation: Department of Pharmacology and Toxicology, University of Innsbruck, Peter-Mayr-Strasse 1, A-6020 Innsbruck, Austria.
authors.forename: Helmut
authors.initials: H
authors.lastname: Prast
authors.affiliation: Department of Pharmacology and Toxicology, University of Innsbruck, Peter-Mayr-Strasse 1, A-6020 Innsbruck, Austria. Electronic address: athineos.philippou@uibk.ac.at.
authors.forename: Athineos
authors.initials: A
authors.lastname: Philippu
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000502:physiology; D018698:Glutamic Acid / Q000378:metabolism; D006834:Hydrazines / Q000494:pharmacology; D020646:Intralaminar Thalamic Nuclei / Q000378:metabolism*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009474:Neurons / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism* / Q000494:pharmacology; D009714:Nucleus Accumbens / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D009435:Synaptic Transmission / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D006834:Hydrazines; C112653:PAPA NONOate; D001224:Aspartic Acid; D009569:Nitric Oxide; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D019331:NG-Nitroarginine Methyl Ester
keywords: Amino acids; Extracellular potentials; In vivo electrophysiology; In vivo release; Nitric oxide; Push–pull superfusion