EN
Current evidence strongly suggests that gap junctions (GJs) communication underlies the mechanisms of oscillation and synchrony in the central nervous system. In our previous work we have documented that GJs are highly involved in the generation of theta rhythm in both in vivo and in vitro hippocampal formation. Specifically, the blockage of gap junction by application of carbenoxolone (CBX) abolished hippocampal theta field potential and this effect was found to be hardly reversible. In our recent studies we have showed that posterior hypothalamic area (PHa), well known as an extrinsic modulator of hippocampal theta frequency, is also capable of independent theta rhythm generation. The aim of the present study was to investigate the effect of gap junctions blockage on cholinergically-induced posterior hypothalamic theta in vitro. Two experimental procedures were applied. (1) PHa slices were preincubated in 100 μM CBX and then theta rhythm was eleicited by 50 μM carbachol (CCH); (2) PHa theta activity was induced by perfusion of the slices with 50 μM CCH, and then the slices were perfused with 50 μM CCH + 100 μM CBX. In both experimental conditions the blockage of gap junctions with carbenoxolone failed to abolish the cholinergic theta rhythm in the posterior hypothalamic area. The mechanisms underlying the generation of PHa theta activity are discussed. Supported by NCN grant 2011/01/B/N24/00373.