RESUMEN
The ventral tegmental area (VTA) is a heterogeneous midbrain structure, containing neurons and astrocytes, that coordinates behaviors by integrating activity from numerous afferents. Within neuron-astrocyte networks, astrocytes control signals from distinct afferents in a circuit-specific manner, but whether this capacity scales up to drive motivated behavior has been undetermined. Using genetic and optical dissection strategies we report that VTA astrocytes tune glutamatergic signaling selectively on local inhibitory neurons to drive a functional circuit for learned avoidance. In this circuit, astrocytes facilitate excitation of VTA GABA neurons to increase inhibition of dopamine neurons, eliciting real-time and learned avoidance behavior that is sufficient to impede expression of preference for reward. Loss of one glutamate transporter (GLT-1) from VTA astrocytes selectively blocks these avoidance behaviors and spares preference for reward. Thus, VTA astrocytes selectively regulate excitation of local GABA neurons to drive a distinct avoidance circuit that opposes approach behavior.
Asunto(s)
Astrocitos/fisiología , Reacción de Prevención/fisiología , Conducta de Elección/fisiología , Área Tegmental Ventral/citología , Sistema de Transporte de Aminoácidos X-AG/metabolismo , Animales , Neuronas Dopaminérgicas/metabolismo , Femenino , Neuronas GABAérgicas/fisiología , Ácido Glutámico/metabolismo , Masculino , Ratones Endogámicos C57BL , Modelos Biológicos , Inhibición NeuralRESUMEN
Carbon prepared from silk cotton hull was used to remove a textile dye (reactive blue MR) from aqueous solution by an adsorption technique under varying conditions of agitation time, dye concentration, adsorbent dose and pH. Adsorption depended on solution pH, dye concentration, carbon concentration and contact time. Equilibrium was attained with in 60 min. Adsorption followed both Langmuir and Freundlich isotherm models. The adsorption capacity was found to be 12.9 mg/g at an initial pH of 2+/-0.2 for the particle size of 125-250 microm at room temperature (30+/-2 degrees C).