| Summary: | Astrocytes in culture display large cytosolic calcium increases upon stimulation with dopamine, however the mechanism and physiological significance of this calcium response is still unknown. In this thesis, I demonstrate that hippocampal astrocytes in situ respond to dopamine with similar large calcium transients. I also describe a novel astrocyte calcium decrease, which appears specific to dopaminergic stimulation. Dopamine is a potent neuromodulator of hippocampal synaptic activity, as are astrocytes. However, I found no evidence to suggest that dopamine-induced calcium transients in astrocytes affect excitatory synaptic transmission and its short-term plasticity in the hippocampal stratum radiatum. In perforant path - CA1 pyramidal synapses of stratum lacunosum-moleculare, astrocytes were found to lessen the inhibitory effect of dopamine on evoked PTP. This work shows for the first time that astrocytes in situ can robustly respond to dopamine with a complex Ca2+ signal thus may participate in dopaminergic signalling in the brain.
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