IFIBYNE   05513
INSTITUTO DE FISIOLOGIA, BIOLOGIA MOLECULAR Y NEUROCIENCIAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Chronic cocaine “binge” alters thalamic glutamic acid decarboxylase (GAD) and CaV3.1 protein levels
Autor/es:
BELÉN GOITIA; MARIANA RAINERI; LAURA E. GONZÁLEZ; JOSÉ LUIS ROZAS; OSVALDO D. UCHITEL; EDGAR GARCIA-RILL; VERÓNICA BISAGNO; FRANCISCO J. URBANO
Lugar:
Washington, DC
Reunión:
Congreso; 41st Meeting of the Society for Neuroscience; 2011
Institución organizadora:
Society for Neuroscience
Resumen:
Our group previously described that a cocaine “binge” (3x15 mg/kg, 1h apart; slices were obtained 1 hour after last injection)induces an enhancement in both GABAergic transmission and T-type calcium currents on Ventrobasal (VB) thalamicneurons. Such effects were prevented by the systemic administration of T-type calcium channel antagonists mibefradil and2-octanol. However, it is unknown if protein levels of the enzymes that synthesize GABA (glutamic acid decarboxylase isoformsGAD65/67) or T-type calcium channel subunits (CaV3.1 and 3.3) are affected by a cocaine “binge”.The objective of this study was to assess the effects of acute and chronic cocaine “binge” administration on protein levelsrelative to actin levels and compared to saline administration, of GAD65/67, CaV3.1 and CaV3.3 T-type calcium channelsubunits using Western Blotting. No changes in the levels of these proteins were observed in either VB or Reticular (Ret)nuclei 1 hour after a cocaine “binge” administration (MANOVA for VB and Ret, p>0.05). Similarly, no changes were observed24 hours after the last “binge” injection (MANOVA for VB and Ret, p>0.05). However, one day after a chronic“binge” protocol (one “binge” a day, for 3 days) an increase in protein levels of CaV3.1 was observed in the VB nucleus(Mean±S.E.M., cocaine=318%±69, n=4; saline=100%±34, n=6; ANOVA p=0.0131). No changes in GAD65/67 levels werefound. After a fourth “binge” administration, no changes were observed in VB CaV3.1 protein levels. Instead, GAD67 levelswere increased in Ret nucleus (1 hour after the fourth binge, cocaine=156%±29, n=4 mice; saline= 100±18, n=3 mice; ANOVAp=0.024). No differences were found in GAD65/67 protein levels in the VB nucleus.In conclusion, T- type and GAD65/67 protein levels were increased by chronic cocaine administration. Changes in the expressionlevels of these two key proteins may help explain the alterations observed in thalamocortical networks of longtermcocaine abusers.