Abstract

GRANA, Daniel R. et al. Effects of Losartan on the Carotid Glomus in Adult Normotensive Rats. Rev. argent. cardiol. [online]. 2006, vol.74, n.6, pp.384-388. ISSN 1850-3748.

We have recently reported serious lesions in the carotid glomus and the autonomic ganglia of SHR rats, and suggested that this effect was due more to an increase in blood pressure than to aging. Subsequently we showed, also in SHR rats, that compared to atenolol, ramipril exerts a protective effect on these structures, well beyond the reduction in blood pressure. Since there are no studies describing the changes caused by AT1 blockade on glomus morphology in normotensive rats, we undertook the present study with the goal of assessing the effect of losartan on the glomus of male Wistar rats treated during 8 months. Fourteen rats aged 4 weeks were divided into two groups: control and losartan (10 mg/kg/day in drinking water). Systolic blood pressure (SBP) was recorded at initiation and monthly thereafter. At the age of 9 months, the rats were sacrificed and their carotid glomus extracted, stained with hematoxilin-eosin and Masson's trichromic and processed for histomorphometry with an image analyzer. In the control group, SBP was 115 ± 8.1 mm Hg, whereas in the losartan group it was 105 ± 8.3 mm Hg (p = 0.0375). As to histomorphometry, the treated group exhibited a larger glomus area compared to the control group (497.931± 48.783 versus 59.668 ± 6.196 µm²; p < 0.0001) and a wall/ lumen ratio in the glomus arterioles of 0.7 ± 0.1 versus 2.7± 0.6, respectively (p < 0.0001). The control group exhibited a decrease in the glomus area and an increase in wall/lumen ratio, suggesting that the atrophy observed with increasing age in the structures analyzed is related to arterial blood supply.

Keywords : Carotid glomus; Losartan; Hypertension; Pathology.