Regulation of noradrenaline release by presynaptic receptor systems.

Inhibition of both noradrenergic and serotonergic neurons in brain by the alpha-adrenergic agonist clonidine.

Distribution of α2 agonist binding sites in the rat and human central nervous system: Analysis of some functional, anatomic correlates of the pharmacologic effects of clonidine and related adrenergic agents

Central α-adrenergic systems as targets for hypotensive drugs

A 300-mug oral dose of clonidine was administered to 5 normal volunteers and measurements of plasma concentration and effects upon blood pressure, heart rate, circulatory reflexes, sedation, and dry mouth were made for the following 8 hr. The plasma concentration rose to a peak of 1.02 +/- 0.52 ng/ml (SD) at 90 min and fell with a mean half-life of 12.7 hr. Blood pressure of the group fell from 111.0/77.0 to 87.2/60.4 after 3 hr and was 95.2/62.2 mm Hg at 8 hr. Heart rate in recumbency was slowed. Marked sedation and a fall in salivary flow followed the same time-course as the plasma concentration. The cold pressor response was reduced but the Valsalva overshoot was little affected.

J. Fichelle

Papers

Cardiovascular effects of 2-(2,6-dichlorophenylamino)-2-imidazoline hydrochloride (ST 115): II. Central sympathetic structures

Cardiovascular effects of 2-(2,6-dichlorophenylamino)-2-imidazoline hydrochloride (ST 155). I. Peripheral sympathetic system.