The content of these European Society of Cardiology (ESC) Guidelines has been published for personal and educational use only. No commercial use is authorized. No part of the ESC Guidelines may be translated or reproduced in any form without written permission from the ESC. Permission can be obtained upon submission of a written request to Oxford University Press, the publisher of the European Heart Journal and the party authorized to handle such permissions on behalf of the ESC. Disclaimer. The ESC Guidelines represent the views of the ESC and were arrived at after careful consideration of the available evidence at the time they were written. Health professionals are encouraged to take them fully into account when exercising their clinical judgement. The guidelines do not, however, override the individual responsibility of health professionals to make appropriate decisions in the circumstances of the individual patients, in consultation with that patient, and where appropriate and necessary the patient's guardian or carer. It is also the health professional's responsibility to verify the rules and regulations applicable to drugs and devices at the time of prescription.

The evidence for the presence of postjunctional alpha 1- and alpha 2-adrenoceptor subtypes in human blood vessels is reviewed. Experiments in healthy subjects are described that show that alpha 1- as well as alpha 2-adrenoceptor mediated vasoconstriction contribute to vascular smooth muscle tone and that adrenaline and noradrenaline have similar affinities for each subtype. In addition, evidence is presented for a preferential intrajunctional location of alpha 1-adrenoceptors and a preferential extrajunctional location of alpha 2-adrenoceptors in human blood vessels. It is concluded that at present postjunctional alpha-adrenoceptors in human blood vessels can be classified as alpha 1 and alpha 2. Despite the fact that both subtypes mediate vasoconstriction, these receptors are likely to subserve different physiological functions.

No abstract

No abstract

Central imidazoline (I(1))-receptors have been recognised as targets of a new class of centrally acting antihypertensives. The stimulation of these I(1)-receptors induces peripheral sympatho-inhibition and a reduction of (elevated) blood pressure. Moxonidine and rilmenidine are the prototypes of this new class of centrally acting antihypertensives. These imidazoline receptor stimulants are effective antihypertensives with a haemodynamic profile which is attractive from a pathophysiological point of view. Since both moxonidine and rilmenidine have a much weaker affinity for central (2)-adrenoceptors than classic centrally acting drugs, for example, clonidine and alpha-methyl-DOPA, the side-effects profile of the I(1)-receptor stimulants is significantly better. The imidazoline (I(1))-receptor stimulants are the subject of the current survey. They appear to offer the possibility of developing centrally acting antihypertensives with the same attractive haemodynamic characteristics as the classic alpha(2)-adrenoceptor stimulants, but with clearly better tolerability. Their potential use in the treatment of congestive heart failure and the metabolic syndrome is subject to clinical investigation.