Neural Mechanisms and Delayed Gastric Emptying of Liquid Induced Through Acute Myocardial Infarction in Rats / Mecanismos Neurais e Retardo do Esvaziamento Gástrico de Liquido Induzido no Infarto Agudo do Miocárdio em Ratos

Background: In pathological situations, such as acute myocardial infarction, disorders of motility of the proximal gut can trigger symptoms like nausea and vomiting. Acute myocardial infarction delays gastric emptying (GE) of liquid in rats. Objective: Investigate the involvement of the vagus nerve, α 1-adrenoceptors, central nervous system GABAB receptors and also participation of paraventricular nucleus (PVN) of the hypothalamus in GE and gastric compliance (GC) in infarcted rats. Methods: Wistar rats, N = 8-15 in each group, were divided as INF group and sham (SH) group and subdivided. The infarction was performed through ligation of the left anterior descending coronary artery. GC was estimated with pressure-volume curves. Vagotomy was performed by sectioning the dorsal and ventral branches. To verify the action of GABAB receptors, baclofen was injected via icv (intracerebroventricular). Intravenous prazosin was used to produce chemical sympathectomy. The lesion in the PVN of the hypothalamus was performed using a 1mA/10s electrical current and GE was determined by measuring the percentage of gastric retention (% GR) of a saline meal. Results: No significant differences were observed regarding GC between groups; vagotomy significantly reduced % GR in INF group; icv treatment with baclofen significantly reduced %GR. GABAB receptors were not conclusively involved in delaying GE; intravenous treatment with prazosin significantly reduced GR% in INF group. PVN lesion abolished the effect of myocardial infarction on GE. Conclusion: Gastric emptying of liquids induced through acute myocardial infarction in rats showed the involvement of the vagus nerve, alpha1- adrenergic receptors and PVN. .

Fundamento: Distúrbios da motilidade do intestino proximal no infarto agudo do miocárdio podem desencadear sintomas digestivos como náuseas e vômitos. O infarto do miocárdio ocasiona retardo do esvaziamento gástrico (EG) de líquido em ratos. Objetivo: Investigar se existe a influência do nervo vago (VGX), adrenoreceptores α-1, receptores GABAB do sistema nervoso central e participação do núcleo paraventricular (NPV) do hipotálamo no esvaziamento gástrico (EG) e complacência gástrica (CG) em ratos infartados. Métodos: Ratos Wistar (n = 8-15) foram divididos em: grupo infarto (INF), sham (SH) e subdivididos. O infarto foi realizado por ligadura da artéria coronária descendente anterior. A complacência gástrica foi estimada com curvas pressão-volume. Realizada vagotomia por secção dos ramos dorsal e ventral. Para verificar a ação dos receptores GABAB foi injetado baclofeno por via intra ventrículo-cerebral. Simpatectomia química foi realizada com prazosina intravenosa (iv), e na lesão do núcleo paraventricular do hipotálamo foi utilizada corrente elétrica de 1mA/10s, com esvaziamento gástrico determinado por medição da retenção gástrica (% RG) de uma refeição salina. Resultados: Não houve diferença significativa na CG. A vagotomia (VGX) reduziu significativamente a %RG; no grupo INF, o tratamento intra ventrículo-cerebral (ivc) com baclofeno reduziu significativamente a % RG; não houve conclusivamente envolvimento dos receptores GABAB em retardar o EG; o tratamento intravenoso com prazosina reduziu significativamente a %RG no grupo INF. A lesão do NPV aboliu o efeito do infarto do miocárdio no EG. Conclusão: O nervo vago, receptores α-adrenérgicos e núcleo paraventricular estão envolvidos no retardo do esvaziamento gástrico no infarto agudo do miocárdio em ratos. .

Neural mechanisms and delayed gastric emptying of liquid induced through acute myocardial infarction in rats.

BACKGROUND: In pathological situations, such as acute myocardial infarction, disorders of motility of the proximal gut can trigger symptoms like nausea and vomiting. Acute myocardial infarction delays gastric emptying (GE) of liquid in rats. OBJECTIVE: Investigate the involvement of the vagus nerve, α 1-adrenoceptors, central nervous system GABAB receptors and also participation of paraventricular nucleus (PVN) of the hypothalamus in GE and gastric compliance (GC) in infarcted rats. METHODS: Wistar rats, N = 8-15 in each group, were divided as INF group and sham (SH) group and subdivided. The infarction was performed through ligation of the left anterior descending coronary artery. GC was estimated with pressure-volume curves. Vagotomy was performed by sectioning the dorsal and ventral branches. To verify the action of GABAB receptors, baclofen was injected via icv (intracerebroventricular). Intravenous prazosin was used to produce chemical sympathectomy. The lesion in the PVN of the hypothalamus was performed using a 1 mA/10 s electrical current and GE was determined by measuring the percentage of gastric retention (% GR) of a saline meal. RESULTS: No significant differences were observed regarding GC between groups; vagotomy significantly reduced % GR in INF group; icv treatment with baclofen significantly reduced %GR. GABAB receptors were not conclusively involved in delaying GE; intravenous treatment with prazosin significantly reduced GR% in INF group. PVN lesion abolished the effect of myocardial infarction on GE. CONCLUSION: Gastric emptying of liquids induced through acute myocardial infarction in rats showed the involvement of the vagus nerve, alpha1- adrenergic receptors and PVN.

Intake of heat-expanded amaranth grain reverses endothelial dysfunction in hypercholesterolemic rabbits.

This study reports the new functional property of amaranth grain against diet-induced endothelial dysfunction in rabbits. Twenty-seven New Zealand rabbits were fed either a standard diet (SD/G1) or a hypercholesterolemic diet (Hichol) for 28 days. On day 29, the Hichol group was subdivided into four groups and begun receiving the following diets for 21 days: G2: SD + amaranth, G3: Hichol + amaranth, G4: SD alone, and G5: Hichol alone, while G1 continued to receive SD for 21 days. Amaranth intake restored endothelial function (G2, G3) to nearly normal during the 21-day recovery besides substantially lowering total and LDL blood cholesterol levels. This effect was not seen by simply correcting the diet (G4). Upon continuance of Hichol, however, amaranth supplementation did show some contribution to the cholesterol-lowering effect (G4 vs. G3). On day 49, feeding Hichol without the help of amaranth, harm was further magnified by lowering HDL-cholesterol (G5). Fecal cholesterol was found increased in groups that ingested amaranth (G2, G3), but no significant impact from either supplementation or diet reversal was found in fecal bile acids. Amaranth supplementation granted some protection against tissue cholesterol (G5) and tissue peroxidation (G3). It is concluded that even in concurrence with a hypercholesterolemic diet, intake of heat-expanded amaranth can revert an associated endothelial dysfunction besides incrementing fecal cholesterol excretion and lowering blood and tissue cholesterol oxidation in dyslipidemic rabbits. These results supported the notion of a lipid peroxidation process occurring with high cholesterol intakes.

Effect of pitavastatin on vascular reactivity in hypercholesterolemic rabbits.

BACKGROUND: Pitavastatin is the newest statin available in Brazil and likely the one with fewer side effects. Thus, pitavastatin was evaluated in hypercholesterolemic rabbits in relation to its action on vascular reactivity. OBJECTIVE: To assess the lowest dose of pitavastatin necessary to reduce plasma lipids, cholesterol and tissue lipid peroxidation, as well as endothelial function in hypercholesterolemic rabbits. METHODS: Thirty rabbits divided into six groups (n = 5): G1 - standard chow diet; G2 - hypercholesterolemic diet for 30 days; G3 - hypercholesterolemic diet and after the 16th day, diet supplemented with pitavastatin (0.1 mg); G4 - hypercholesterolemic diet supplemented with pitavastatin (0.25 mg); G5 - hypercholesterolemic diet supplemented with pitavastatin (0.5 mg); G6 - hypercholesterolemic diet supplemented with pitavastatin (1.0 mg). After 30 days, total cholesterol, HDL, triglycerides, glucose, creatine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT) were measured and LDL was calculated. In-depth anesthesia was performed with sodium thiopental and aortic segments were removed to study endothelial function, cholesterol and tissue lipid peroxidation. The significance level for statistical tests was 5%. RESULTS: Total cholesterol and LDL were significantly elevated in relation to G1. HDL was significantly reduced in G4, G5 and G6 when compared to G2. Triglycerides, CK, AST, ALT, cholesterol and tissue lipid peroxidation showed no statistical difference between G2 and G3-G6. Significantly endothelial dysfunction reversion was observed in G5 and G6 when compared to G2. CONCLUSION: Pitavastatin starting at a 0.5 mg dose was effective in reverting endothelial dysfunction in hypercholesterolemic rabbits.

Effect of Pitavastatin on Vascular Reactivity in Hypercholesterolemic Rabbits / O Efeito da Pitavastatina na Reatividade Vascular em Coelhos Hipercolesterolêmicos

Background: Pitavastatin is the newest statin available in Brazil and likely the one with fewer side effects. Thus, pitavastatin was evaluated in hypercholesterolemic rabbits in relation to its action on vascular reactivity. Objective: To assess the lowest dose of pitavastatin necessary to reduce plasma lipids, cholesterol and tissue lipid peroxidation, as well as endothelial function in hypercholesterolemic rabbits. Methods: Thirty rabbits divided into six groups (n = 5): G1 - standard chow diet; G2 - hypercholesterolemic diet for 30 days; G3 - hypercholesterolemic diet and after the 16th day, diet supplemented with pitavastatin (0.1 mg); G4 - hypercholesterolemic diet supplemented with pitavastatin (0.25 mg); G5 - hypercholesterolemic diet supplemented with pitavastatin (0.5 mg); G6 - hypercholesterolemic diet supplemented with pitavastatin (1.0 mg). After 30 days, total cholesterol, HDL, triglycerides, glucose, creatine kinase (CK), aspartate aminotransferase (AST), alanine aminotransferase (ALT) were measured and LDL was calculated. In-depth anesthesia was performed with sodium thiopental and aortic segments were removed to study endothelial function, cholesterol and tissue lipid peroxidation. The significance level for statistical tests was 5%. Results: Total cholesterol and LDL were significantly elevated in relation to G1. HDL was significantly reduced in G4, G5 and G6 when compared to G2. Triglycerides, CK, AST, ALT, cholesterol and tissue lipid peroxidation showed no statistical difference between G2 and G3-G6. Significantly endothelial dysfunction reversion was observed in G5 and G6 when compared to G2. Conclusion: Pitavastatin starting at a 0.5 mg dose was effective in reverting endothelial dysfunction in hypercholesterolemic rabbits. .

Fundamento: A pitavastatina é a mais nova estatina disponível no Brasil e com prováveis menores efeitos colaterais. Assim, a pitavastatina foi avaliada em coelhos hipercolesterolêmicos em relação à ação na reatividade vascular. Objetivo: Investigar a menor dose de pitavastatina na redução dos lípides plasmáticos, colesterol e peroxidação lipídica tecidual e função endotelial em coelhos hipercolesterolêmicos. Métodos: Trinta coelhos divididos em seis grupos (n=5): G1 - dieta ração padrão; G2 - dieta hipercolesterolêmica por 30 dias; G3 - dieta hipercolesterolêmica e a partir do 16º dia suplementada com pitavastatina (0,1 mg); G4 - dieta hipercolesterolêmica e suplementada com pitavastatina (0.25 mg); G5 - dieta hipercolesterolêmica e suplementada com pitavastatina (0,5 mg); G6 - dieta hipercolesterolêmica e suplementada com pitavastatina (1,0 mg). Após 30 dias foram dosados o colesterol total, HDL, triglicérides, glicose, creatinoquinase, aspartato aminotransferase, alanina aminotransferase e o LDL calculado. Aprofundada a anestesia com tiopental sódico e retirado segmentos de aorta para estudo da função endotelial, colesterol e peroxidação lipídica tecidual. O nível de significância adotado para os testes estatísticos foi 5%. Resultados: Colesterol total e LDL elevados significativamente em relação ao G1. HDL reduzida significativamente em G4, G5 e G6 em relação ao G2. Triglicérides, creatinoquinase, aspartato aminotransferase, alanina aminotransferase, colesterol e peroxidação lipídica tecidual sem diferença estatística entre G3-G6 e G2. Disfunção endotelial revertida significativamente em G5 e G6 em relação ao G2. Conclusão: A pitavastatina, a partir da ...

Evolution and involution of atherosclerosis and its relationship with vascular reactivity in hypercholesterolemic rabbits.

BACKGROUND AND OBJECTIVES: The aim of this study is to verify the evolution and involution of experimental atherosclerosis in rabbits through the study of endothelial function, lipids and tissue lipid peroxidation, macro and microscopic quantification of aortic atherosclerosis. METHODS: Thirty male New Zealand white rabbits were divided into six groups (n=5): G1 normal diet; G2: hypercholesterolemic receiving 0.5% of cholesterol diet for 4 months; G3: hypercholesterolemic diet for 4 months after normal diet for more 4 months; G4: hypercholesterolemic diet for 4 months plus normal diet and rosuvastatin for 1 month, G5: hypercholesterolemic diet for 4 months plus normal diet and rosuvastatin for 2 months, G6: hypercholesterolemic diet for 4 months plus normal diet and rosuvastatin for 4 months. Rosuvastatin was administered at a dosage of 5mg dissolved in 150 ml of water daily. At the end of the experiment were measured: total cholesterol (TC), triglycerides (TG), low density lipoprotein (LDL-C), high density lipoprotein (HDL-C), tissue cholesterol (CAO), lipid peroxidation tissue (MDA). Endothelial function (RMAX) was studied in a segment of thoracic aorta, through curve-effect of acetylcholine and sodium nitroprusside. The amount of atherosclerosis was determined by measurement of the arterial lesion, through software, after staining with Sudan IV and histological staining. RESULTS: In relation the water the rabbits drank 60-70 ml all day. It was seen significantly increase in all parameters at G2 both biochemical and tissue. In the group G3 it was seen significantly decrease in plasma lipids levels and tissue cholesterol. Treated groups G4, G5 and G6 all showed a decreased plasma lipid levels, only at G6 group it was noted a tissue cholesterol, tissue peroxidation and quantification of atherosclerosis, which showed a significant decrease. In relation the endothelial function only G6 improve significantly. INTERPRETATION AND CONCLUSIONS: Our findings indicated that the treatment with rosuvastatin for 4 months is more efficient because improve the endothelial function significantly.

Inibidores da enzima de conversão da angiotensina e infarto agudo do miocárdio. Estudo experimental em ratos / Angiotensin converting enzyme inhibitors and acute myocardial infarction. Experimental study in rats

JUSTIFICATIVA E OBJETIVOS: O uso dos inibidores da enzima de conversão da angiotensina por períodos prolongados de utilização, tem demonstrado sua eficiência em reduzir a mortalidade em portadores de ICC após infarto agudo do miocárdio. Há controvérsias em relação a quando iniciar o tratamento destes fármacos na fase peri-infarto do miocárdio, ou seja, antes ou precocemente após o infarto. O objetivo deste estudo foi avaliar a capacidade de três inibidores da enzima de conversão da angiotensina (IECA) em reduzir a mortalidade e a extensão do infarto agudo experimental em ratos, em dois esquemas posológicos diferentes. MÉTODO: Ratos Wistar, machos, foram infartados por ligadura da artéria coronária descendente anterior e distribuído em três grupos: 1, 2 e 3 e três subgrupos: A, B, C : 1A e 2A - captopril (40 e 12,5 mg/kg); 1B e 2B - cilazapril (8 e 2 mg/kg); 1C e 2C - enalapril (16 e 5 mg/kg). O grupo 3 constituiu o grupo controle. Os fármacos foram administrados 48h antes e 48h após o infarto. A coloração pelo cloreto de trifenil tetrazólio (TTC) e o exame histológico foram utilizados para verificação da extensão do infarto. Observou-se a mortalidade após a instalação do infarto. Utilizou-se o teste Qui-quadrado para avaliação estatística, sendo considerado significativo o valor de p < 0,05. RESULTADOS: No subgrupo 1A a mortalidade foi menor que nos subgrupos 1B e 1C, mas não foi significante em relação ao grupo D. A mortalidade no subgrupo 1C foi maior que no grupo D. Não houve diferença significativa entre a mortalidade nos subgrupos 2A, 2B e 2C. Em relação à extensão do infarto não houve diferença significativa entre os quatro grupos. CONCLUSÃO: Os IECA estudados não reduziram a mortalidade e a extensão do infarto agudo experimental do miocárdio em ratos nas doses e períodos em que estas foram avaliadas.

Ação do lisinopril e do losartan na função endotelial após infarto agudo do miocárdio. Estudo experimental em ratos / Action of lisinopril and losartan in endothelial function after acute myocardialinfarction. Experimental study in rats.

JUSTIFICATIVA E OBJETIVOS: O presente estudo teve como objetivo estudar a influência do lisinopril e do losartan na função endotelial em ratos com infarto experimental do miocárdio. MÉTODO: Ratos Wistar machos, peso entre 350 e 400 g, divididos em quatro grupos (n igual 10): G1 igual ratos controle sem infarto, G2 igual ratos com infarto, G3 igual ratos com infarto e tratados com lisinopril (20 mg/kg/dia) e G4 igual ratos com infarto e tratados com losartan (30 mg/kg/dia). Os fármacos foram administrados via gavagem dois dias antes do infarto e continuado por mais sete dias. Os ratos foram anestesiados com éter para a ligadura da coronária descendente anterior. Após nove dias os animais foram anestesiados, o coração excisado e verificado a extensão do infarto. Utilizou-se para este fim a coloração pelo método do cloreto de trifeniltetrazólio a 1%, se considerando infarto grande quando excedia 40% da área do ventrículo esquerdo. A função endotelial foi verificada através de curva de concen­tração efeito com acetilcolina em segmento proximal da aorta torácica. Foram utilizados os testes estatísticos de ANOVA e de Duncan, sendo considerado significativo o valor de p menor que 0,05. RESULTADOS: Os resultados obtidos para a função en­dotelial para o relaxamento máximo foram: G 1 igual 78,24% mais ou menos 3,57%; G2 igual 14,04% mais ou menos 5,20%, G3 igual 48,94% mais ou menos 9,29% e G4 igual 26,98% mais ou menos 7,80%. Houve diferença estatístíca significatíva para entre os G3 e G4. CONCLUSÃO: Ocorreu disfunção endotelial em ratos na fase recente do infarto do miocárdio e o tratamento com lisinopril e losartan melhoraram esta disfunção endotelial.

[Gastric emptying of liquids in rats submitted to acute myocardial infarction]. / Vaciamiento gástrico de líquidos en ratas sometidas a infarto del miocardio.

Gastric Emptying (GE) is food transition from the stomach to the upper small intestine. Haemodynamics changes modify gastric emptying and the gastroduodenal motor activity. Myocardial Infarction is a pathological condition in which there are haemodynamics changes. Therefore, the objective of the present investigation was to study the effect of acute myocardial infarction on rat gastric emptying of an isosmotic and inert liquid meal. We conducted a study involving male Wistar rats (varying in body weight from 220 g to 250 g), that were allowed to habituate in a laboratory environment and then divided into 3 groups: group INF, rats in which the myocardial infarction was produced by left anterior coronary artery ligation; group SH, rats in which the myocardial infarction was simulated without ligating the anterior coronary artery; and group NA, rats which were not given any anesthesia or surgical procedures. After group constitution, animals were fasted with access to water ad libitum. 24 hours later, the Gastric Retention (GR) of 1.5 ml/100 g animal weight of a test meal of 0.9% NaCl plus the marker phenol red was evaluated. GE was indirectly evaluated in conscious animals, through determining the percentage of gastric retention (% GR) of a test meal, measured 10 minutes after orogastric infusion. Results of the present study showed that animals from the INF group presented GR (median=48.0%), significantly higher than the NA group (30.6%) and SH group (36.6%). No statistical difference in GR was observed between the SH and NA groups. Infarcted area, expressed in percentages, in animals of the INF group was 51.3+/-4.7% (mean SEM, N=17) which not presented correlation with results of GR of the same group (r=-0.05). From a caloric viewpoint, the results suggested that acute myocardial infarct in rats induce delay of the gastric emptying of an isosmotic and inert liquid meal.

Vaciamiento gástrico de líquidos en ratas sometidas a infarto del miocardio / Gastric emptying of liquids in rats submitted to acute myocardial infarction

El vaciamiento gástrico (VG) es la transferencia del contenido gástrico al intestino delgado. Las alteracioneshemodinámicas modifican el VG y la actividad motora gastroduodenal. El infarto del miocardio (IM) es una condición patológica en la que hay alteraciones hemodinámicas. Siendo así, el objetivo de este trabajo fue evaluar el efecto del infarto agudo del miocardio sobre el vaciamiento gástrico de una comida líquida isosmótica e inerte desde el punto de vista calórico (soluciónsalina). Fueron utilizadas ratas Wistar machos, con un peso de 220-250g, adaptados a condiciones de laboratorioy divididos en 3 grupos: grupo INF (N=17), ratas con infarto del miocardio por ligadura de la arteria coronaria descendiente anterior izquierda; grupoSH (N=15), Sham en las que fue simulado el proceso quirúrgico, sin ligadura de la arteria coronaria; grupoNA (N=15), ratas en las que no fue hecho ningún procedimiento de sedación o quirúrgico. Los animales, después de la constitución de los grupos, permanecieron en ayuno recibiendo agua ad libitum. Veinticuatro horas después fue evaluado el VG de 1,5 ml/100g de peso de animal de una comida de prueba (CP) salinamarcada con fenol rojo. El VG fue evaluado indirectamente en los animales despiertos a través de la determinacióndel porcentaje de retención gástrica (RG) de la CP, 10 minutos después de administración de oro gástrico.Los resultados mostraron que los animales del grupo INF presentaron RG (media=48,0%) significativamentemás alta con relación a los animales del grupo NA (30,6%,) y el grupo SH (36,6%). No hubo diferenciaentre animales del grupo SH con relación a los del grupo NA. El área de infarto, expresada en porcentaje,en los animales del grupo INF fue de 51,3±4,7% ( ±SE, N=17) y no presentó correlación con los resultadosde RG del mismo grupo (r=-0,05).

Gastric Emptying (GE) is food transition from the stomach to the upper small intestine. Haemodynamics changes modify gastric emptying and the gastroduodenal motor activity. Myocardial Infarction is a pathological condition in which there are haemodynamics changes. Therefore, the objective of the present investigation was to study the effect of acute myocardial infarction on rat gastric emptying of an isosmotic and inert liquid meal. We conducted a study involving male Wistar rats (varying in body weight from 220 g to 250 g), that were allowed to habituate in a laboratory environment and then divided into 3 groups: group INF, rats in which the myocardial infarction was produced by left anterior coronary artery ligation; group SH, rats in which the myocardial infarction was simulated without ligating the anterior coronary artery; and group NA, rats which were not given any anesthesia or surgical procedures. After group constitution, animals were fasted with access to water ad libitum. 24 hours later, the Gastric Retention (GR) of 1.5 ml/100 g animal weight of a test meal of 0.9% NaCl plus the marker phenol red was evaluated. GE was indirectly evaluated in conscious animals, through determining the percentage of gastric retention (% GR) of a test meal, measured 10 minutes after orogastric infusion. Results of the present study showed that animals from the INF group presented GR (median=48.0%), significantly higher than the NA group (30.6%) and SH group (36.6%). No statistical difference in GR was observed between the SH and NA groups. Infarcted area, expressed in percentages, in animals of the INF group was 51.3+/-4.7% (mean SEM, N=17) which not presented correlation with results of GR of the same group (r=-0.05). From a caloric viewpoint, the results suggested that acute myocardial infarct in rats induce delay of the gastric emptying of an isosmotic and inert liquid meal.

Vaciamiento gástrico de líquidos en ratas sometidas a infarto del miocardio / Gastric emptying of liquids in rats submitted to acute myocardial infarction

El vaciamiento gástrico (VG) es la transferencia del contenido gástrico al intestino delgado. Las alteracioneshemodinámicas modifican el VG y la actividad motora gastroduodenal. El infarto del miocardio (IM) es una condición patológica en la que hay alteraciones hemodinámicas. Siendo así, el objetivo de este trabajo fue evaluar el efecto del infarto agudo del miocardio sobre el vaciamiento gástrico de una comida líquida isosmótica e inerte desde el punto de vista calórico (soluciónsalina). Fueron utilizadas ratas Wistar machos, con un peso de 220-250g, adaptados a condiciones de laboratorioy divididos en 3 grupos: grupo INF (N=17), ratas con infarto del miocardio por ligadura de la arteria coronaria descendiente anterior izquierda; grupoSH (N=15), Sham en las que fue simulado el proceso quirúrgico, sin ligadura de la arteria coronaria; grupoNA (N=15), ratas en las que no fue hecho ningún procedimiento de sedación o quirúrgico. Los animales, después de la constitución de los grupos, permanecieron en ayuno recibiendo agua ad libitum. Veinticuatro horas después fue evaluado el VG de 1,5 ml/100g de peso de animal de una comida de prueba (CP) salinamarcada con fenol rojo. El VG fue evaluado indirectamente en los animales despiertos a través de la determinacióndel porcentaje de retención gástrica (RG) de la CP, 10 minutos después de administración de oro gástrico.Los resultados mostraron que los animales del grupo INF presentaron RG (media=48,0%) significativamentemás alta con relación a los animales del grupo NA (30,6%,) y el grupo SH (36,6%). No hubo diferenciaentre animales del grupo SH con relación a los del grupo NA. El área de infarto, expresada en porcentaje,en los animales del grupo INF fue de 51,3±4,7% ( ±SE, N=17) y no presentó correlación con los resultadosde RG del mismo grupo (r=-0,05).(AU)

Gastric Emptying (GE) is food transition from the stomach to the upper small intestine. Haemodynamics changes modify gastric emptying and the gastroduodenal motor activity. Myocardial Infarction is a pathological condition in which there are haemodynamics changes. Therefore, the objective of the present investigation was to study the effect of acute myocardial infarction on rat gastric emptying of an isosmotic and inert liquid meal. We conducted a study involving male Wistar rats (varying in body weight from 220 g to 250 g), that were allowed to habituate in a laboratory environment and then divided into 3 groups: group INF, rats in which the myocardial infarction was produced by left anterior coronary artery ligation; group SH, rats in which the myocardial infarction was simulated without ligating the anterior coronary artery; and group NA, rats which were not given any anesthesia or surgical procedures. After group constitution, animals were fasted with access to water ad libitum. 24 hours later, the Gastric Retention (GR) of 1.5 ml/100 g animal weight of a test meal of 0.9% NaCl plus the marker phenol red was evaluated. GE was indirectly evaluated in conscious animals, through determining the percentage of gastric retention (% GR) of a test meal, measured 10 minutes after orogastric infusion. Results of the present study showed that animals from the INF group presented GR (median=48.0%), significantly higher than the NA group (30.6%) and SH group (36.6%). No statistical difference in GR was observed between the SH and NA groups. Infarcted area, expressed in percentages, in animals of the INF group was 51.3+/-4.7% (mean SEM, N=17) which not presented correlation with results of GR of the same group (r=-0.05). From a caloric viewpoint, the results suggested that acute myocardial infarct in rats induce delay of the gastric emptying of an isosmotic and inert liquid meal.(AU)

Vaciamiento gástrico de líquidos en ratas sometidas a infarto del miocardio / Gastric emptying of liquids in rats submitted to acute myocardial infarction

El vaciamiento gástrico (VG) es la transferencia del contenido gástrico al intestino delgado. Las alteracioneshemodinámicas modifican el VG y la actividad motora gastroduodenal. El infarto del miocardio (IM) es una condición patológica en la que hay alteraciones hemodinámicas. Siendo así, el objetivo de este trabajo fue evaluar el efecto del infarto agudo del miocardio sobre el vaciamiento gástrico de una comida líquida isosmótica e inerte desde el punto de vista calórico (soluciónsalina). Fueron utilizadas ratas Wistar machos, con un peso de 220-250g, adaptados a condiciones de laboratorioy divididos en 3 grupos: grupo INF (N=17), ratas con infarto del miocardio por ligadura de la arteria coronaria descendiente anterior izquierda; grupoSH (N=15), Sham en las que fue simulado el proceso quirúrgico, sin ligadura de la arteria coronaria; grupoNA (N=15), ratas en las que no fue hecho ningún procedimiento de sedación o quirúrgico. Los animales, después de la constitución de los grupos, permanecieron en ayuno recibiendo agua ad libitum. Veinticuatro horas después fue evaluado el VG de 1,5 ml/100g de peso de animal de una comida de prueba (CP) salinamarcada con fenol rojo. El VG fue evaluado indirectamente en los animales despiertos a través de la determinacióndel porcentaje de retención gástrica (RG) de la CP, 10 minutos después de administración de oro gástrico.Los resultados mostraron que los animales del grupo INF presentaron RG (media=48,0%) significativamentemás alta con relación a los animales del grupo NA (30,6%,) y el grupo SH (36,6%). No hubo diferenciaentre animales del grupo SH con relación a los del grupo NA. El área de infarto, expresada en porcentaje,en los animales del grupo INF fue de 51,3±4,7% ( ±SE, N=17) y no presentó correlación con los resultadosde RG del mismo grupo (r=-0,05).(AU)

Gastric Emptying (GE) is food transition from the stomach to the upper small intestine. Haemodynamics changes modify gastric emptying and the gastroduodenal motor activity. Myocardial Infarction is a pathological condition in which there are haemodynamics changes. Therefore, the objective of the present investigation was to study the effect of acute myocardial infarction on rat gastric emptying of an isosmotic and inert liquid meal. We conducted a study involving male Wistar rats (varying in body weight from 220 g to 250 g), that were allowed to habituate in a laboratory environment and then divided into 3 groups: group INF, rats in which the myocardial infarction was produced by left anterior coronary artery ligation; group SH, rats in which the myocardial infarction was simulated without ligating the anterior coronary artery; and group NA, rats which were not given any anesthesia or surgical procedures. After group constitution, animals were fasted with access to water ad libitum. 24 hours later, the Gastric Retention (GR) of 1.5 ml/100 g animal weight of a test meal of 0.9% NaCl plus the marker phenol red was evaluated. GE was indirectly evaluated in conscious animals, through determining the percentage of gastric retention (% GR) of a test meal, measured 10 minutes after orogastric infusion. Results of the present study showed that animals from the INF group presented GR (median=48.0%), significantly higher than the NA group (30.6%) and SH group (36.6%). No statistical difference in GR was observed between the SH and NA groups. Infarcted area, expressed in percentages, in animals of the INF group was 51.3+/-4.7% (mean SEM, N=17) which not presented correlation with results of GR of the same group (r=-0.05). From a caloric viewpoint, the results suggested that acute myocardial infarct in rats induce delay of the gastric emptying of an isosmotic and inert liquid meal.(AU)

Vaciamiento gástrico de líquidos en ratas sometidas a infarto del miocardio. / [Gastric emptying of liquids in rats submitted to acute myocardial infarction]

Gastric Emptying (GE) is food transition from the stomach to the upper small intestine. Haemodynamics changes modify gastric emptying and the gastroduodenal motor activity. Myocardial Infarction is a pathological condition in which there are haemodynamics changes. Therefore, the objective of the present investigation was to study the effect of acute myocardial infarction on rat gastric emptying of an isosmotic and inert liquid meal. We conducted a study involving male Wistar rats (varying in body weight from 220 g to 250 g), that were allowed to habituate in a laboratory environment and then divided into 3 groups: group INF, rats in which the myocardial infarction was produced by left anterior coronary artery ligation; group SH, rats in which the myocardial infarction was simulated without ligating the anterior coronary artery; and group NA, rats which were not given any anesthesia or surgical procedures. After group constitution, animals were fasted with access to water ad libitum. 24 hours later, the Gastric Retention (GR) of 1.5 ml/100 g animal weight of a test meal of 0.9

NaCl plus the marker phenol red was evaluated. GE was indirectly evaluated in conscious animals, through determining the percentage of gastric retention (

GR) of a test meal, measured 10 minutes after orogastric infusion. Results of the present study showed that animals from the INF group presented GR (median=48.0

), significantly higher than the NA group (30.6

) and SH group (36.6

). No statistical difference in GR was observed between the SH and NA groups. Infarcted area, expressed in percentages, in animals of the INF group was 51.3+/-4.7

(mean SEM, N=17) which not presented correlation with results of GR of the same group (r=-0.05). From a caloric viewpoint, the results suggested that acute myocardial infarct in rats induce delay of the gastric emptying of an isosmotic and inert liquid meal.

Efeito da fluvastantina sobre os lípides, a peroxidação lípida e a disfunção endotelial em coelhos hipercolesterolêmicos / Effects of fluvastatin on lipids, lipid peroxidation and endothelial dysfunction in hypercholesterolaemic rabbits

O principal objetivo do estudo é detectar o efeito da fluvastatina no relaxamento dependente do endotélio, o conteúdo de colesterol na pareda da aorta, quantificar o malondialdeido (MDA) nas LDLs nativa e oxidada, assim como na parede da aorta em coelhos hipercolesterolêmicos. Coelhos machos da raça Nova Zelândia foram randomizados em três grupos: controle normal, controle, hipercolesterolêmico e fluvastatina (n=10). Todos os animais foram alimentados com dieta suplementada com gordura de coco 2 por cento e colesterol 0,5 por cento w/w por 45 dias. Após 15 dias, amostra de sangue foi obtida via punção cardíaca para determinação de colesterol plasmático total. Então, foi administrado, por gavagem, fluvastatina na dose de 40mg/dias aos animais do grupo fluvastatina. No final do experimento, nova amostra de sangue foi retirada para determinação de colesterol e isolamento de LDL. Os animais foram sacrificados por deslocamento da coluna cervical após anestesia com éter. Toracotomia mediana foi realizada e a aorta removida para preparação de anéis para estudo do relaxamento dependente do endotélio, medida do colesterol tecidual, MDA na parede da aorta e LDLs. Os resultados foram comparados por métodos estatísticos não paramétricos. Os resultados mostram que a fluvastatina, significantemente, reduziu o colesterol plasmático total, LDL-colesterol, colesterol na parede da aorta, reduziu o MDA nas LDLs nativa e oxidada, assim como na parede da aorta. A fluvastatina foi eficaz em melhorar o relaxamento dependente do endotélio de modo significante. os autores discutem o efeito benéfico das estatinas relacionados à redução do colesterol plasmático e à redução do MDA determinada pela fluvastatina e consideram que isso pode dever-se a mecanismos específicos relacionados a receptores de membrana ou à moléculas de sinalização intracelular que estão envolvidos na produção de NO°. Outra questão refere-se à selectividade e disponibilidade das estatinas. Os autores enfatizam que estudos similares podem corroborar na direção de verificar se diferenças entre as estatinas são relevantes na prática clínica, considerando que todas elas determinam inquestionável redução na mortalidade e eventos coronarianos observados em estudos clínicos.