ABSTRACT
Glutamate is the most important excitatory transmitter in the mammalian brain. All pyramidal cells in the cerebral cortex and granule cells in the cerebellar cortex release glutamate. The potential at which there is no net current is the reversal potential. So, the reversal potential can be a good clue to the ions responsible for generating the synaptic potential. A population of receptors called α-amino-3-hydroxy-5-methyl-4-isoxazole-proprionic acid (AMPA)/kainate receptors mediate most fast glutamate neurotransmission. AMPA/kainate receptors are ligand-gated ion channels, transmembrane proteins with an intrinsic ion channel and a recognition site for glutamate on the extracellular face that projects into the synaptic cleft. Pyramidal cells in the cerebral cortex have many γ-aminobutyrate (GABA)ergic synapses impinging on them from interneurons called basket cells. Hence in response to the release of GABA the permeability of the pyramidal cell to chloride ions increases. GABAA receptors are members of the ligand-gated superfamily of receptors and are responsible for all fast GABA transmission.
