[Effects of acute and chronic treatment with an adrenergic alpha receptor agonist, LE S3341, on the rate of catecholamine turnover in various peripheral organs and brain structures in the rat].

The turnover of catecholamines (CA) in some peripheral tissues and various areas of the rat brain was estimated by measuring the amine depletion after inhibition of their biosynthesis by alpha-methyl-p-tyrosine (alpha-MPT). Acute or chronic treatment with S3341 (3mg/kg i.p.) reduced NA turnover in submaxillary glands, brain stem and rest of the brain but had no effect on NA turnover in the hypothalamus. The dopamine (DA) levels were unaltered following chronic S3341 treatment but the alpha-MPT induced disappearance of DA was significantly retarded in the striatum and rest of the brain. The results of the present study demonstrate that no tolerance to the effect of S3341 on brain CA turnover develops during chronic drug administration. The central biochemical effects of S3341 appear different from those of other agonists of central alpha 2-adrenoceptors such as clonidine.