Brain sites for the antihypertensive action of clonidine.

In conclusion, I reviewed recent literature that directly investigated the site and mechanism of action of clonidine in the central nervous system. One can interpret these data in the following manner. In the medulla, clonidine is acting as an alpha-adrenergic receptor antagonist that inhibits excitatory input to the sympathetic nervous system. In the anterior hypothalamus, clonidine is acting as an alpha-adrenergic receptor agonist that excites an inhibitory pathway which inhibits excitatory input to the sympathetic nervous system. Both actions produce the same final response; that is, diminished sympathetic outflow from the central nervous system.