Evaginación ventricular izquierda congénita y foramen oval permeable: una combinación potencialmente embolígena / Congenital left ventricular outpouching and patent foramen ovale: A potentially emboligenic combinatio

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Inhibitory effect of N(G)-nitro-L-arginine methyl ester on the anti-adrenergic response elicited by ayanin in the pithed rat.

In this study we evaluated the anti-adrenergic response elicited by ayanin, a flavonoid compound isolated from Croton schiedeanus Schlecht, in the pithed rat, and the inhibitory effect of NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME), and its acute toxicity profile in mice. In pithed rats ayanin (5 - 50 mg/kg i. v.) caused a dose-dependent decrease in the pressor and chronotropic responses induced by intravenous noradrenaline administration (0.25 microg/kg). This anti-adrenergic response was completely abolished by prior treatment with L-NAME (10 mg/kg i.v ) and the inhibitory effect of L-NAME was reversed after intravenous administration of L-arginine (100 mg/kg, i. v.). No lethal or major toxic effects were observed in mice receiving i. p. administration of ayanin up to a dose of 500 mg/kg. Our findings confirm that ayanin exerts protective cardiovascular effects against the increase in blood pressure and heart rate mainly through a mechanism that depends on the NO/cyclic guanosine monophosphate (cGMP) pathway without acute toxic effects. These results suggest that extracts of Croton schiedeanus, the native south American plant from which ayanin was isolated, might be beneficial in cardiovascular disease.

Antihypertensive and vasorelaxant effects of aqueous extract from Croton schiedeanus Schlecht in rats.

Antihypertensive and vasorelaxant effects of treatment with the aqueous extract of Croton schiedeanus Schlecht (AECS) were investigated in anaesthetized spontaneously hypertensive rats (SHR). Intravenous bolus injections of AECS (5-100 mg/kg) elicited dose-dependent decreases in mean arterial pressure (MAP) and heart rate (HR). Additionally, AECS (10(-6)-3x10(-3)g/ml) completely relaxed the contractions induced by high K(+) concentrations in intact rat aortic rings in a concentration-dependent manner.

Role of intrarenal endothelin 1, endothelin 3, and angiotensin II expression in chronic cyclosporin A nephrotoxicity in rats.

Endothelin 1 (Et1) is widely expressed in the kidney and is related to several functions and to pathological conditions with progression towards sclerosis. The function of endothelin 3 (Et3) at the renal level is debatable, but it could have an important regulatory function in the reabsorption of water through its action on tubular type B receptors. Angiotensin II has recently been implicated as the principal factor responsible for the progression of interstitial fibrosis induced by cyclosporin A (CsA). We investigated this relationship in vivo and analyzed the modifications induced by CsA toxicity in Sprague-Dawley rats treated with 25 mg/kg/day of CsA for 28 and 56 days. Immunohistochemical methods and molecular analysis were used to study the expression of Et1 and Et3 and immunohistochemistry alone to determine the intrarenal expression of angiotensin II. Rats treated with CsA developed chronic nephrotoxicity lesions; semiquantitative analyses of hyaline arteriolopathy revealed that the passage of time affected the extent of this lesion and led to the diminution of the total glomerular area. Immunohistochemical results showed that chronic CsA treatment induced moderate secretion of Et1 and Et3 at tubular and glomerular levels and that the local expression of angiotensin II in the treatment groups was more evident than in control animals. Besides, the mRNA levels of preproEt3 showed a dramatic increase from 28 days after CsA treatment (control group 0.07+/-0.11 vs. CsA group 0.48+/-0.11, p<0.01), while the mRNA levels of preproEt1 increased from 56 days (control group 0.15+/-0.05 vs. CsA group 0.34+/-0.09, p< 0.05). At 28 days, renal lesions correlated strongly with the mRNA levels of Et3 (r>0.50, p<0.01). However, at 56 days, the key finding was the strong correlation of the most important analytical, histological, and immunohistochemical parameters of CsA nephrotoxicity with Et1 mRNA levels (r>0.50, p<0.01). These results support the hypothesis that the clinical and morphological phenomena linked with CsA nephrotoxicity are related to hypersecretion of endothelins and local expression of angiotensin II in the outer medulla and medullary rays; Et3 and angiotensin II are the first to act, followed subsequently by Et1.

Chemical studies on Mexican plants used in traditional medicine, III: New 4-phenylcoumarins from Exostema caribaeum.

Investigation of the MeOH extract of Exostema caribaeum (Rubiaceae) led to the isolation of three new 4-phenylcoumarins. Their structures, 5-O-beta-D-galactosyl-7-methoxy-3',4'-dihydroxy-4-phenylcoumarin [1a] 7,4',5'-trihydroxy-4-phenyl-5,2'-oxidocoumarin [2a] and 7,4'-dimethoxy-5'-hydroxy-4-phenyl-5,2'-oxido-coumarin [3a] were elucidated by spectral methods and chemical transformations. It was also demonstrated that 4-phenylcoumarins undergo oxidative cyclization under basic conditions in the presence of air to give 4-phenyl-5,2'-oxido-coumarins.

Techniques for the lesion of the vomeronasal organ of the rat.

Two technical procedures were developed in order to suppress the vomeronasal organ (V.O.) of the rat. The organ was approached through the nasal or oral cavity and electrolytic or thermic lesions were respectively performed. For electrolytic lesions the projection of the organ on the nasal bone was first determined. After opening the nasal bones, the Vs. Os. were lesioned by way of an electric current applied through an electrode introduced between the mucosa and nasal septum. For thermic lesions, the projection of the V.O. on the palate's surface was determined. After opening this area and the underlying part of the maxillary bone, both Vs. Os. were cauterized.

Techniques for the lesion of the vomeronasal organ of the rat.

Two technical procedures were developed in order to suppress the vomeronasal organ (V.O.) of the rat. The organ was approached through the nasal or oral cavity and electrolytic or thermic lesions were respectively performed. For electrolytic lesions the projection of the organ on the nasal bone was first determined. After opening the nasal bones, the Vs. Os. were lesioned by way of an electric current applied through an electrode introduced between the mucosa and nasal septum. For thermic lesions, the projection of the V.O. on the palates surface was determined. After opening this area and the underlying part of the maxillary bone, both Vs. Os. were cauterized.

Techniques for the lesion of the vomeronasal organ of the rat

Two technical procedures were developed in order to suppress the vomeronasal organ (V.O.) of the rat. The organ was approached through the nasal or oral cavity and electrolytic or thermic lesions were respectively performed. For electrolytic lesions the projection of the organ on the nasal bone was first determined. After opening the nasal bones, the Vs. Os. were lesioned by way of an electric current applied through an electrode introduced between the mucosa and nasal septum. For thermic lesions, the projection of the V.O. on the palate’s surface was determined. After opening this area and the underlying part of the maxillary bone, both Vs. Os. were cauterized.