COCAINE ACUTE “BINGE” ADMINISTRATION ABNORMALLY ENHANCE THALAMIC GABERGIC SYNAPTIC TRANSMISSION IN MICE.

BISAGNO VERONICA; RAINERI MARIANA; WIKINSKI SILVIA; UCHITEL OSVALDO; LLINAS RODOLFO; URBANO FRANCISCO

Huerta Grande

Congreso; IRCN First Joint Meeting of the Argentine Society for Neurosciences (SAN) and the Argentine Workshop in Neurosciences (TAN); 2009

Synaptic Trasmissions And ExcitabilityPoster Number (253) Session IIICOCAINE ACUTE “BINGE” ADMINISTRATION ABNORMALLYENHANCE THALAMIC GABERGIC SYNAPTIC TRANSMISSIONIN MICE.Bisagno Veronica1, Raineri Mariana1, Wikinski Silvia 1, UchitelOsvaldo 2, Llinas Rodolfo3, Urbano Francisco 21Instituto de Investigaciones Farmacológicas (ININFA- CONICET-UBA), Junín956, piso 5, C1113-Buenos Aires, Argentina. , 2Laboratorio de Fisiología y BiologíaMolecular, Instituto de Fisiología, Biología Molecular y Neurociencias (LFBMIFIBYNE),CONICET-UBA, Intendente Guiraldes 2670, pabellón 2, piso 2, C. Univer.,3Department of Physiology & Neuroscience, New York University School ofMedicine, 550 First Avenue, NY10016, New York, USA.fjurbano@fbmc.fcen.uba.arAttentional and sensorial processing deficits in cocaine addicts arerelevant to cocaine abuse treatment. Thalamocortical system is involvedin sensory processing, however, little is known about possible mechanismsmediating cocaine effects on the thalamocortical circuitry. Thalamicventrobasal nucleus (VB) is known to be densely innervated by GABAergicterminals from reticular neurons. Here we studied whether cocaine acute“binge” (3x15mg injections 1 h apart) would enhance GABAergic feed-backtransmission from reticular to VB neurons. In vitro, voltage clamp recordings ofVB thalamic neurons in the presence of TTX, AP5, CNQX showed higher levelsof GABA-A-mediated synaptic transmission lasting over 24 hours after lastinjection of cocaine. Indeed, mIPSCs recorded from VB neurons presented anincrement in amplitudes and higher frequencies compared to saline, partiallyreverted after 24 hr. Also immunohistochemical experiments were performedon brain slices containing primary somatosensory cortex (S1) and thalamicnuclei using antibodies for GAD 65/67 in saline and cocaine groups. Nosignificant differences were found on immunostaining levels. Bath applicationof the D2/D3-agonist Ropinirole enhanced GABA-A minis amplitudes whilereducing their inter-event intervals. Thus, these results suggest a possiblerole of D2/D3 receptors in VB’s GABA-A minis enhancement induced bycocaine. Supported by: ANPCyT PICT 2007-01009 and PIDRI-PRH 2007 (toDr. Urbano), Wellcome Trust, 068941/Z/02/Z; grant#6220; UBACYT X223;ANPCyT PICT2006-199 (to Dr. Uchitel), NIH NS13742 (to Dr. Llinás) and PICT31953 (ANPCyT), PIP 5870 (CONICET) and UBACYT M073 (to Dr. Wikinski).