Dissociation between the circulating renin-angiotensin system and angiotensin II receptors in central losartan-induced hypertension

Losartan, an AT1 angiotensin II (ANG II) receptor non-peptide antagonist, induces an increase in mean arterial pressure (MAP) when injected intracerebroventricularly (icv) into rats. The present study investigated possible effector mechanisms of the increase in MAP induced by icv losartan in unanesthetized rats. Male Holtzman rats (280-300 g, N = 6/group) with a cannula implanted into the anterior ventral third ventricle received an icv injection of losartan (90 µg/2 µl) that induced a typical peak pressor response within 5 min. In one group of animals, this response to icv losartan was completely reduced from 18 ± 1 to 4 ± 2 mmHg by intravenous (iv) injection of losartan (2.5-10 mg/kg), and in another group, it was partially reduced from 18 ± 3 to 11 ± 2 mmHg by iv prazosin (0.1-1.0 mg/kg), an alpha1-adrenergic antagonist (P<0.05). Captopril (10 mg/kg), a converting enzyme inhibitor, injected iv in a third group inhibited the pressor response to icv losartan from 24 ± 3 to 7 ± 2 mmHg (P<0.05). Propranolol (10 mg/kg), a ß-adrenoceptor antagonist, injected iv in a fourth group did not alter the pressor response to icv losartan. Plasma renin activity and serum angiotensin-converting enzyme activity were not altered by icv losartan in other animals. The results suggest that the pressor effect of icv losartan depends on angiotensinergic and alpha1-adrenoceptor activation, but not on increased circulating ANG II.

Medial septal area ANG II receptor subtypes in the regulation of urine and sodium excretion induced by vasopressin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Role of the medial septal area on pilocarpine-induced salivary secretion and water intake

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Central mechanisms involved in pilocarpine-induced pressor response

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Changes in taste reactivity to intra-oral hypertonic NaCl after lateral parabrachial injections of an alpha(2)-adrenergic receptor agonist

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Commissural NTS lesions enhance the pressor response to central cholinergic and adrenergic activation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Accurate Approach in the Treatment of Oral Bisphosphonate-Related Jaw Osteonecrosis

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is not completely understood and difficult to treat. Even though the occurrence of BRONJ is mainly related to the therapy with intravenous bisphosphonates (BPs), this article reports a case of long-term oral BP use and BRONJ occurrence. In addition, a literature review provides some additional information about BPs, BRONJ, and also a guideline for the prevention and treatment of BRONJ stages. A 79-year-old patient presented intense and persistent pain, purulent secretion, and exposed bone at the right side of the lower jaw. Thus, she was submitted to anamnesis, radiologic and tomographic examinations, and bacterial culture and sensitivity tests. These procedures were followed by surgical debridement of the bone and surrounding tissues/cyst and antibiotic prescription and histopathologic analysis of the fragments. Together, the examinations performed showed the occurrence of stage 2 BRONJ. Moreover, the antibiotic prescription, discontinuation of oral BP, and surgical procedures ensure that the patient had no more symptoms. Therefore, considering the presented case, we believe that an accurate approach is promising to diagnose and treat stage 2 BRONJ and other associated pathologic findings.

Cordia verbenacea and secretion of mast cells in different animal species

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Mechanisms of the Gastric Antiulcerogenic Activity of Anacardium humile St. Hil on Ethanol-Induced Acute Gastric Mucosal Injury in Rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of essential oil obtained from Croton cajucara Benth. on gastric ulcer healing and protective factors of the gastric mucosa

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Anti-hemorrhagic Activity of Four Brazilian Vegetable Species Against Bothrops jararaca Venom

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of Spider Venom Toxin PWTX-I (6-Hydroxytrypargine) on the Central Nervous System of Rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Endurance training improves responsiveness to insulin and modulates insulin signal transduction through the phosphatidylinositol 3-kinase/Akt-1 pathway

Background: Endurance training increases insulin-stimulated muscle glucose transport and leads to improved metabolic control in diabetic patients.Objective: To analyze the effects of endurance training on the early steps of insulin action in muscle of rats. Design: Male rats submitted to daily swimming for 6 weeks were compared with sedentary controls. At the end of the training period, anesthetized animals received an intravenous (i.v.) injection of insulin and had a fragment of their gastrocnemius muscle excised for the experiments.Methods: Associations between insulin receptor, insulin receptor substrates (IRS)-1 and -2 and phosphatidylinositol 3-kinase (PI3-kinase) were analyzed by immunoprecipitation and immunoblotting. Akt-1 serine phosphorylation and specific protein quantification were detected by immunoblotting of total extracts, and IRS-1/IRS-2-associated PI3-kinase activity were determined by thin-layer chromatography.Results: Insulin-induced phosphorylation of IRS-1 and IRS-2 increased respectively by 1.8-fold (P < 0.05) and 1.5-fold (P < 0.05), whereas their association with PI3-kinase increased by 2.3-fold (P < 0.05) and 1.9-fold (P < 0.05) in trained rats as compared with sedentary controls, respectively. The activity of PI3-kinase associated with IRS-1 and IRS-2 increased by 1.8-fold (P < 0.05) and 1.7-fold (P < 0.05) respectively, in trained rats as compared with their untrained counterparts. Serine phosphorylation of Akt-1/PKB increased 1.7-fold (P < 0.05) in trained rats in response to insulin. These findings were accompanied by increased responsiveness to insulin as demonstrated by a reduced area under the curve for insulin during an i.v. glucose tolerance test, by increased glucose disappearance rate during an insulin tolerance test, and by increased expression of glucose transporter-4.Conclusions: the increased responsiveness to insulin induced by chronic exercise in rat skeletal muscle may result, at least in part, from the modulation of the insulin signaling pathway at different molecular levels.

Spirulina, exercício e controle da glicemia em ratos diabéticos

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Exercise and spirulina control non-alcoholic hepatic steatosis and lipid profile in diabetic Wistar rats

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)