[Imidazol receptor agonists--new possibilities for treating hypertension]

Adrenergic alpha 2-receptors mediate important regulatory functions in both the brain and the periphery. Activation of these receptors lowers blood pressure through a decrease in sympathetic and vasomotor nerve activity. Agonists of the alpha 2-adrenoceptors are often used in the treatment of arterial hypertension. As recently discovered, their chemical structure includes so called "imidazoline ring" and compounds with such chemical structure bind to nonadrenergic sites known as imidazoline receptors. These receptors are localized in midportions of the brain but they are also present in other organs such as lungs, heart, adrenal medulla, liver and kidneys. Their selective activation lowers blood pressure without inducing sedation typical for alpha 2-agonists. Several substances binding with high selectivity to imidazoline receptors have recently been synthesized. Some of them as rilmenidine and moxonidine have successfully been introduced to the treatment of arterial hypertension in humans.