Electrical coupling underlies theta rhythm in freely moving cats

The role of gap junction coupling in the generation of theta rhythms in freely moving cats was investigated in a present study. Two gap junction blockers, carbenoxolone and quinine, were administered intraperitoneally and intrahippocampally; both gap junction blockers abolished or diminished (respectively) hippocampal formation theta. The inhibitory effect developed approximately 30 min after drug administration. This effect was found to be reversible. Our results provide the first direct in vivo evidence for the contribution of gap junction communication in mechanisms of neural synchrony, underlying the production of theta in in vivo conditions.