Effect of TGF-beta1 on long-term synaptic plasticity and distribution of AMPA receptors in the CA1 field of the hippocampus

Using the methods of electrophysiology and immunohistochemistry, the effect of the transforming factor beta-1(TGF-β1), an anti-inflammatory cytokine, on the long-term post-tetanic potentiation (LTP) in CA1 field hippocampal slices and the distribution of the GluR1 subunit of the AMPA receptor has been studied. It was shown that TGF-β1 at a concentration of 10 ng/ml did not significantly affect the initial stage of LTP and substantially changed the distribution of synaptic AMPA receptors in response to tetanic stimulation. Twenty five minutes after the tetanization, the main pool of AMPA receptors (90%) was due to the postsynaptic density (PSD). By contrast, LTP in the presence of TGF-β1 was accompanied by less pronounced changes in the distribution of AMPA receptors. Their localization in both pre- and postsynaptic regions remained nearly the same as that in the control. It may be suggested that the normal distribution of AMPA receptors in spinous synapses promotes the stabilization of potentiated synapses, thereby retaining LTP for longer terms.