Figure 1.

GHB and baclofen elicit [Ca²⁺]_i transients in VTA and thalamic astrocytes. (a) Fluorescence images of Fluo-4-loaded rat VTA slices before (control) and during a brief bath application of 10 mM GHB (top) or 10 µM baclofen (bottom) show robust and synchronous [Ca²⁺]_i transients in response to both drugs. The transients evoked in astrocytes in the two experiments are shown in fluorescence plots on the right. (b) Dose–response curves of the number of astrocytes responding to GHB and baclofen (number of slices is indicated below each data point). (c) Fluorescence plots from different preparations of mouse and rat VTA and VB thalamus show that GABA_BR activation resulting in [Ca²⁺]_i elevations is a general mechanism, i.e. it can be observed in different species and brain regions. Glutamate (100 µM) applications are also shown for comparison. (Online version in colour.)