Effect of epidermal growth factor on adrenaline induced effects in isolated rabbit heart

Acute psychological stressors induce damage in organs as heart. Catecholamines are responsible for acute stress effects. Adrenaline, through 1-adrenergic receptors; stimulates EOF release to the blood. Because plasma catecholamine concentration is high during the stress and afterwards, organs are exposed to combined effects of both catecholamines and EGF. Intermale fighting [IF stress model] does not raise plasma creatine kinase [CK] activity ,while increases plasma transaminase and lactate dehydrogenase [LDH] activities, So the heart is protected. EGF may protect the heart against the harmful effects of epinephrine. The present research studied EGF administration on adrenaline induced effects in the rabbit heart [invitro] of 8 groups of male white New Zealand rabbits. Heart tissues were excised and incubated. revealed a significant decrease in heart rate, contractility and coronary flow rate in Epidermal growth factor gp. A non significant change in heart rate and coronary flow rate and heart contractility after infusion of alpha blocker and adrenaline.While a significant decrease in heart rate, heart contractility and coronary flow rate in either adrenaline with beta Blocker group and or EGF with adrenaline and a blocker group. EGF with adrenaline and beta Blocker group produced a significant increase in heart rate, heart contractility and coronary flow rate. In spite of EGF positive effects on heart properties, it interfered with the adrenaline positive effects through Beta receptors

Exercício físico e memória / Physical exercise and memory

A memória é susceptível às influências endógena, hormonal e neuro-humoral especialmente logo após a aquisiçäo da informaçäo. A amígdala, o septo medial, o hipocampo e o córtex entorrinal estäo envolvidos nos processos de consolidaçäo, armazenamento e evocaçäo. A resposta ao problema dos mecanismos de armazenamento podem encontrar-se tanto pelo caminho da potenciaçäo delonga duraçäo como pelo das redes neurais, através de uma interaçäo complementar. A modulaçäo da memória enfoca a atençäo na análise das condiçöes sob as quais a consolidaçäo da memória pode ser alterada. Uma informaçäo adquirida em um determinado contexto neuro-humoral será melhor evocada se durante o processo de evocaçäo o contexto neuro-humoral for similar ao do momento da aquisiçäo, caracterizando a existência de uma periférica pós-treino de hormônios normalmente liberados por experiências emocionais e estresses, tais como: catecolaminas, ACTH, vasopressina, além do peptídio opióide B-endorfina. Os hormônios e opióides envolvidos na regulaçäo da memória também estäo envolvidos na regulaçäo, homeostática do exercício. Estudos têm demonstrado que a liberaçäo das catecolaminas, vasopressina, ACTH e B-endorfina é estimulada pelo exercício, fazendo-se uma relaçäo do efeito do exercício na regulaçäo da memória, especialmente exercícios intensos e os moderados de longa duraçäo

Sistema adrenérgico en los residentes de grandes alturas / Adrenergic system at high altitude population

Heart rate (FC) response to perfusion with isoprenaline is decreased in sealevel natives on expuser to high altitude hypoxia. Since noredraline concentration in plasma is elevated under these condition as phenomenon of downregulation of the betareceptors (BAR) cuold be evoked. For the fisrt time, this aspect was explored in a population native from and residing at 3600 m consisting of normocythemics (HAN) and polycythemics (HAP). the results were compared to those obtained from a sealevel population, exmined in normoxia (SLN) at 4800 m (J. Appl. Physiol. 65:1975-61, 1988). The dose necessary to increase FC by 25 beats per min (125) was identical for HAN and HAP as well as SLN. This iondicates that the chronotropic responses is igual in the two populations when they are studied in their habitual environment; to the contrary, this response is diminished in SLH, thus correlating to the phenomenon of downregulation.

Estudo comparativo da atividade fibrinolítica do plasma de rato em fibrina humana, bovina e murina / A comparative study of fibrinolytic activity of rat plasm in human, bovine e murine fibrin

Vários estudos mostram que o sangue humano lisa espontaneamente enquanto o sangue de outras espécies animais necessitam de altas concentraçöes de ativadores. Nossos resultados mostram que o plasma de rato näo tratado é capaz de lisar a fibrina murina, mas näo a fibrina humana ou bovina. Porém, quando tratamos estes animais com adrenalina, um conhecido ativador do sistema fibrinolítico, o plasma destes animais é capaz de digerir a fibrina humana e bovina. Estes resultados mostram que o uso da fibrina adequada para cada espécie de animal estudado pode evitar resultados discrepantes nos diferentes laboratórios que estudam atividade fibrinolítica

Behavior effects of adrenaline and noradrenaline injected into the lateral ventricles of the pigeon (Columba Livia)

The behavioral effects of intravrnticular 1-micronl injections of adrenaline and noradrenaline (both in a concentration of 30 nmol/micronl) were wxamined in pigeons bearing cannule chronically implanted into the lateral ventricles. Injections of either catcholoamine evoked immediate and intense bouts of feeding behavior, followed by long-lasting incrases in sleep duration (50-90% higher than vehicle-treated subjects) in pigeons given free access to food during the observation period. Pigeons treated with adrenaline or vehicle only, and placed in a cage without the feeder set (food-deprived durngi the observation period), exhibited late increases in exploratory and preening behaviors, and less sleep than controls (vehicle-treated pigeons with free access to food). These data suggest that post-prandial sleep in this situation may represent a by-product of feeding-related processes evoked by both catecholamines

Efecto de monoaminas sobre la secreción de ACTH en células dispersas, perfundidas, de la adenohipófisis del pato barcinochico (anasflavirostris) / Effect of monoamines on ACTH secretion by dispersed, perfused cells from the adenohypophysis of the barcino chico duck (Anas flavirostris)

Continuando con la caracterización de los factores que intervienen en el control de la secreción de ACTH por parte de las células corticomelanotropas de la hipófisis de las aves, hemos probado, utilizando un modelo in vitro de perfusión continua de células adenohipofisarias de pato, el efecto sobre la liberación de ACTH de diversas aminas biógenas y neurofármacos: noradrenalina (NA), adrenalina (A), dopamina (DA), serotonina (5-HT), fenilefrina (Phe), e isoproterenol (IP). Las respuestas obtenidas se comparon con las ejercidas por extractos de eminencia media de hipotálamo de pato (EMP). El orden de "actividad intrínseca (Vmáx) fue: NA+A>Phe>DA=5-HT. Las sustancias fueron probadas en un rango de dosis de 10**-4 a 10**-9M. Todas las sustancias ensayadas resultaron ser agonistas parciales respecto del efecto de EMP. La actividad intrínseca de los más potentes agonistas ensayados, NA y A,fue de 0,66 respecto de la alcanzada por EMP. Se concluye que en el pato, las células corticomelanotropas segregan ACTH en respuesta a NA y A en dosis compatibles con un papel fisiológico de las mencionadas catecolaminas, lo que hace presumir que estas sustancias pueden naturalmente controlar la secreción de ACTH en las aves por acción directa sobre la hipófisis. 5-HT y DA se comportaron como agonistas muy débiles sobre la liberación de ACTH por las células CM del pato en el sistema empleado