Resumo

CARRERO, Celeste; GUERRI GUTTENBERG, Roberto; GRANA, Daniel  e  MILEI, José. Carotid Barochemoreceptors: Target Organs of Arterial Hypertension. Rev. argent. cardiol. [online]. 2007, vol.75, n.3, pp.202-206. ISSN 1850-3748.

The carotid body (CB) is the main peripheral arterial chemoreceptor, able to sense changes in PaO₂, PaCO₂ and pH, and translate them into nervous signals that regulate ventilating, circulating and endocrine responses which allow adaptation to hypoxemia, acidosis, and hypercapnia. The carotid sinus, located next to the CB, with a baroreceptor function, generates cardiovascular responses that decrease arterial hypertension. Both structures are innervated by the carotid sinus nerve (CSN), which is projected to the solitary tract nucleus (STN), closely inter-related and called barochemoreceptors. Lately, these organs have been considered key in the regulation of homeostatic cardiorespiratory responses that could be intimately related to the development and maintenance of arterial hypertension (AHT). There is scant information on the structural changes that occur in these organs during AHT and/or as its consequence. Our hypothesis is that carotid barochemoreceptors would be a new "target organ" of the AHT. In several studies performed in humans and in models of systolic hypertension in animals we observed a severe damage in the CB which was significantly correlated with elevation of the AT. Hence, considering that the renin-angiotensin-aldosterone system (RAAS) would play a significant role in the pathophysiology of the observed injury, we showed that ramipril versus atenolol has a protective effect on the CB further to the mere decrease of the AT. Even though the animal models used had normal pressure, losartan showed this protective effect. Our findings indicate that the CB behaves as a target organ in AHT and the activation of a local RAAS would be responsible for the morphological and functional changes that were observed.

Palavras-chave : Baroreceptors; Chemoreceptors; Carotid body; Hypertension; Systemic Arterial.

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