Acute exposure to dopaminergic neurotoxicants inhibits Ca²⁺ transients in striatal astrocytes.

<p>(a,b) Application of 10 nM–10 µM ATP resulted in Ca²⁺ transients in striatal astrocytes that persisted for greater than 60 sec. (c,d) Addition of MPP⁺ to the imaging media at increasing concentrations acutely suppressed ATP-induced Ca²⁺ transients. Representative traces of astrocytic responses to 1 µM ATP (black arrowhead indicates time of ATP addition) in the presence of MPP⁺ (10 nM–10 µM) indicate dose-dependent suppression of intracellular Ca²⁺ transients. (e,f) Application of 6-OHDA to the imaging media acutely suppressed ATP-induced Ca²⁺ transients. Representative traces of the response to 1 µM ATP in the presence of 6-OHDA (10 nM–10 µM) indicate dose-dependent suppression of intracellular Ca²⁺ transients, where as the dopamine metabolite, DOPAC (10 µM), did not affect the amplitude of Ca²⁺ transients. (a,c,e) Vertical bars denote 1 relative fluorescent unit; horizontal bars denote 10 sec. n = 3 independent experiments; data collected from 50–60 cells group from 2–3 microscopic fields; *<i>p</i><0.05 relative to control, ** <i>p</i><0.01 relative to control and treated groups.