[Synaptic physiology of the kainate receptors and its influence in epileptogenesis]

The kainate receptor is a component of the glutamate signalling system in the nervous system that has remained quite elusive to investigators over the years. Lack of specific pharmacological tools has hampered the detection of these receptors in neurons of the central nervous system as well as the determination of their physiological roles. Cloning of the subunits which make up the kainate receptors, evidence of their existence as independent receptors in neurons and the discovery of selective pharmacological agents have paved the way to define the processes in which these receptors are involved. Indeed, a considerable amount of data indicates that kainate receptors are at both sides of the synapse. Pre and postsynaptic kainate receptors have important roles in maintaining tissue excitability and are able to regulate transmission of information in number of synapses. Ultimate experiments indicate that kainate receptors may be novel targets for antiepileptogenic drugs and illustrate that they have a dual signalling mechanism: they are ion channels but they also are able to trigger a cascade of second messengers by activating a G-protein.