Distribution of [3H]clonidine binding sites in the brain of the convulsive mutant quaking mouse: a radioautographic analysis

Abstract The radioautographic analysis of [ 3 H]clonidine binding was performed on brain slices from the convulsive mutant mice quaking and their controls of the same strain. In the quaking mice significant increases were observed mostly in the brainstem and the cerebellum, but also in a few regions of the forebrain, such as the lateral and medial thalamic nuclei, the medial geniculate nucleus, the amygdala and the hypothalamus. Other regions, such as the cerebral cortex and the hippocampus, which are classically involved in various models of epilepsy, but not in the quaking mice, did not show any modification of [ 3 H]clonidine binding. A high degree of correlation was found between the structures with an increased density of α 2 -adrenoceptor binding sites and the distribution of regions from which seizures can be elicited by intracerebral electrical stimulation in head-restrained quaking mice. This comparison emphasizes the role of noradrenaline acting at the level of α 2 -adrenoceptors in the epileptic syndrome of the quaking mutants.