Nicotinic potentiation of glutamatergic synapses in the prefrontal cortex: New insight into the analysis of the role of nicotinic receptors in cognitive functions

In contrast with the now well‐recognized effects of nicotine in promoting learning and memory, little is known about the functional and pharmacological properties of putative nicotinic acetylcholine receptors located in neocortical areas involved in cognitive functions. Recent electrophysiological experiments using intracellular recordings in the rat prefrontal cortex in vitro have revealed that nicotine selectively enhances the amplitude of excitatory postsynaptic potentials mediated by glutamate in pyramidal cells. The effect was blocked by the specific nicotinic antagonists neuronal bungarotoxin and dihydro‐β‐erythroidine. Several arguments suggest that the potentiation of excitatory potentials by nicotine is due to the activation of presynaptic nicotinic receptors located on glutamatergic afferent terminals. Thus the control by nicotinic receptors of the effectiveness of excitatory inputs to the prefrontal cortex might influence significantly the processing of information in this area. The possibility of a functional cooperation between nicotinic and glutamatergic systems in the neocortex provides an integrative mechanism for the involvement of both neurotransmitter systems in synaptic plasticity underlying memory processes.