The Role of Astrocytic Cx43 in Baseline Synaptic Response and Short Term Synaptic Plasticity in CA1 Area of the Hippocampus

Astrocytic connexins (Cxs) play roles in ion diffusion to the extracellular milieu and in release of ATP and gliotransmitters including glutamate. Connexin 43 (Cx43) is one of the most abundant Cxs in brain tissue, especially in the hippocampus, so, we investigated its role on CA1 baseline synaptic response and short term synaptic plasticity.

In this experimental study, bilateral intrahippocampal microinjection of TAT-Gap19, Cx43 blocker (1nmol/1μl) was performed for inhibition of hippocampal astrocytic connexin 43. Baseline synaptic response and short term synaptic plasticity were evaluated by field potential recording.

 According to two-way ANOVA, inhibition of hippocampal Cx43 did not have any effect on baseline synaptic response (P>0.05). TAT-Gap19 decreased paired pulse index (PPI) at 20 and 80 ms inter pulse intervals (IPI, Unpaired t-test, P<0.05), but it did not affect PPI at 200 ms IPI (P>0.05).

The results suggest that the function of hippocampal astrocytic Cx43 does not affect baseline synaptic response but affects short term synaptic plasticity in CA1 area of the hippocampus.