Interactions of Taurine and Adenosine in the Mouse Hippocampus in Normoxia and Ischemia
Adenosine acts as an inhibitory neuromodulator in the brain through three types of receptors, namely A1, A2, (two subtypes A2A and A2B), and A31. By means of presynaptic A1 receptors adenosine inhibits neurotransmitter release mainly in excitatory synapses, reducing thus neuronal excitability2. Postsynaptically, adenosine hyperpolarizes the postsynaptic membrane through A, receptors by increasing Ca2+ -dependent K+ conductance. Depolarization with K+, electrical stimulation and various agents, including ionotropic glutamate receptor agonists, induce adenosine release 2. Furthermore, adenosine is released during hypoxia and ischemia3, acting then as an endogenous neuroprotectant against cerebral ischemia and excitotoxic neuronal damage4. Similar neuroprotective effects have also been assigned to taurine, a putative inhibitory neuromodulator5, which is also released from nervous tissue under various cell-damaging conditions6. Being particularly enriched in the brain of immature animals, taurine has been thought to have a special function, being essential for the development and survival of neural cells7.8. We now characterized interactions in the release of taurine and adenosine from hippocampal slices from developing (7-day-old) and adult (3month-old) mice in normal conditions and in ischemia, using a superfusion system7.
KeywordsDepression Ischemia Attenuation Adenosine Taurine
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