Kainate receptors: from synaptic activity to disease

Kainate receptors (KARs) are glutamate receptors that participate in the postsynaptic transmission of information and in the control of neuronal excitability, as well as presynaptically modulating the release of the neurotransmitters GABA and glutamate. These modulatory effects, general follow a biphasic pattern, with low KA concentrations provoking an increase in GABA and glutamate release, and higher concentrations mediating a decrease in the release of these neurotransmitters. In addition, KARs are involved in different forms of long‐ and short‐term plasticity. Importantly, altered activity of these receptors has been implicated in different central nervous system diseases and disturbances. Here, we describe the pre‐ and postsynaptic actions of KARs, and the possible role of these receptors in disease, a field that has seen significant progress in recent years. Kainate receptors (KARs) located in the axons of interneurons contacting CA1 pyramidal cells (PC) mediate a decrease in GABA release altering the excitation/inhibition balance. KARs located at CA1 pyramidal neurons increase excitability of these cells by decreasing the after hyperpolarization currents altering the excitation/inhibition balance in the same direction. This unbalance mediated by the activation of pre‐ and postsynaptic KARs is one proposed mechanism for epilepsy in the hippocampus.