Noradrenergic modulation of seizure activity.

Abstract

The mechanisms underlying pathogenesis of epileptic rections have been studied insufficiently as yet. Therefore, it is considered that determining the structures, transmitters, and receptors of the brain, which putatively produce development and intensity modulation of the convulsions, is highly important. The locus coeruleus is a norepinephrinic structure and an endogenous modulator of epilepsy, determining a role of which in a course of seizure reactions is an important problem of epileptology. The goal of the study was assessment of importance of the norepinephrine synapses in development of the local hippocampal seizure activity. The studies were carried out in adult rats, in conditions of chronic experiments. Influences of microinjections of agonist (clonidine) and antagonist (yohimbine) of the alpha-2 norepinephrine receptors on a course of local hippocampal seizure reactions (without behavioral manifestation), have been evaluated. It was found that microinjection of alpha-2 norepinephrine receptors' agonist determined a blockage of the local hippocampal seizures, while alpha-2 norepinephrine receptors' antagonist increased the seizures' power. It is suggested that the effects of locus coeruleus are determined by activation of the alpha-2 norepinephrine receptors.