| Popis: |
Despite intense research efforts, the etiology of primary hypertension remains ill-defined. During our work on molecular influences of lifestyle factors on hypertension, the question arose to what extent cellular and molecular events could be involved in alcohol-induced hypertension. There is increasing evidence that alcohol initiates central as well as peripheral reactions which in a synergistic manner have a hypertensive action. Thus, alcohol diminishes the baro (presso) reflex by interacting with receptors in the brain stem, i.e. nucleus tractus solitarii and rostral ventrolateral medulla. In addition, alcohol induces an increased sympathetic outflow, most probably linked to secretion of corticotropin-releasing hormone. The increased sympathetic outflow is expected not only to induce adrenoceptor-mediated reactions (vasoconstriction, heart rate increase) but to stimulate oxidation reactions. Deleterious peripheral actions result from acetaldehyde which binds to macromolecules if the abundance of cysteine and glutathione is limited. This acetaldehyde induced reduction of low molecular weight thiol compounds can be interpreted as "oxidative stress" which has various unfavourable consequences. The hypertensive action of alcohol should be taken into account when discussing its potential protective influence on coronary risk. |
