Phasic nicotinic potentiation of frog retinotectal transmission facilitates activation of NMDA receptors of tectum column

Abstract

We have recently demonstrated that the intrinsic recurrent excitatory activity of the tectum column increases due to the phasic (after-burst) nicotinic potentiation of a frog single axon retinotectal transmission to the tectum layer F. In the present study we show that the phasic nicotinic potentiation facilitates activation of the NMDA receptors of the tectum column. With this, a functional significance of nicotinic modulation of the activity of the tectum column has been demonstrated, since the activation of NMDA receptors leads to the higher activity level of the tectumn column at which output signals from the tectum column are generated. The nicotinic facilitation of transition of the tectum column to the higher level of activity can be considered as a mechanism of vigilance and cue detection at the level of a small neural network.