Short Term Exposure to Ketamine Reduces Cholinergic Synaptic Transmission, But Not Post-Tetanic Potentiation in Central Neurons

The NMDA receptors are thought to be the main target site for the actions of dissociative ketamine. In addition, ketamine has also been shown to affect myriad brain regions and functions, including learning and memory. However, the precise target sites and the mechanisms underlying ketamine actions in the mammalian central nervous system (CNS) remain poorly defined, mainly due to anatomical constraints, and our inability to access individual pre and postsynaptic neurons. Within the CNS of Lymnaea, the neurons visceral dorsal 4 (VD4) and left pedal dorsal 1 (LPeD1) form an excitatory cholinergic synapse which recapitulates reliably in vitro. Cell culture and electrophysiological techniques were used in this study to determine the effects of ketamine on synaptic transmis sion and post tetanic potentiation (PTP) at the VD4-LPeD1 synapse.