RESUMO
The aim of the present experiment was to evaluate the role played by aspartic acid and glutamic acid of frontal cerebral cortex during the hyperthermia induced by prostaglandin E1. Two groups of six Sprague Dawley male rats were anaesthetized with ethyl-urethane. The frontal cortical concentrations of aspartic and glutamic acids, the firing rate of the sympathetic nerves to the interscapular brown adipose tissue, the colonic and interscapular brown adipose tissue temperatures were monitored both before and after an intracerebroventricular injection of prostaglandin E1 (500 ng) or saline. Aspartic and glutamic acids were collected using a microdialysis probe placed in the frontal cortex. Concentrations of aspartic and glutamic acids were measured by high-pressure liquid chromatography with fluorescence detector. Prostaglandin E1 induced an increase in the concentrations of aspartic and glutamic acids, in the firing rate of sympathetic nerves and in the colonic and interscapular brown adipose tissue temperatures. The findings of the present experiment indicate that an intracerebroventricular injection of prostaglandin E1 causes release of aspartic and glutamic acids in the frontal cortex.
Assuntos
Alprostadil/toxicidade , Ácido Aspártico/metabolismo , Febre/metabolismo , Febre/fisiopatologia , Lobo Frontal/metabolismo , Ácido Glutâmico/metabolismo , Sistema Nervoso Simpático/fisiopatologia , Tecido Adiposo Marrom/fisiopatologia , Alprostadil/administração & dosagem , Animais , Regulação da Temperatura Corporal/efeitos dos fármacos , Colo/fisiopatologia , Febre/induzido quimicamente , Injeções Intraventriculares , Masculino , Microdiálise , Ratos , Ratos Sprague-Dawley , Sistema Nervoso Simpático/efeitos dos fármacosRESUMO
The firing rate of the posterior hypothalamic neurones and interscapular brown adipose tissue and colonic temperatures (TIBAT and TC) were monitored in 36 urethane-anaesthetized male Sprague-Dawley rats before and after an intracerebroventricular (i.c.v.) injection of 400 ng prostaglandin E1 (PGE1) or saline. The i.c.v. injection was preceded by functional decortication in half of each group. The results show an increase of firing rate, TIBAT and TC after PGE1 injection in the rats without decortication. Functional decortication significantly reduced these enhancements. These findings demonstrate that the posterior hypothalamus plays a significant role in the hyperthermia induced by PGE1 and that the cerebral cortex is involved in the control of posterior hypothalamic activity.
Assuntos
Alprostadil , Córtex Cerebral/fisiopatologia , Febre/induzido quimicamente , Febre/fisiopatologia , Hipotálamo Posterior/fisiopatologia , Tecido Adiposo Marrom/fisiopatologia , Animais , Temperatura Corporal , Colo/fisiopatologia , Eletrofisiologia , Hipotálamo Posterior/patologia , Injeções Intraventriculares , Masculino , Neurônios/fisiologia , Ratos , Ratos Sprague-DawleyRESUMO
The sympathetic firing rate of the nerves innervating interscapular brown adipose tissue (IBAT), IBAT and colonic temperatures (TIBAT and TC) were monitored in urethane-anaesthetized male Sprague-Dawley rats. These variables were measured for a period of 40 min before (baseline values) and 40 min after a 2 mg NG-methyl-L-arginine (NMA) injection plus an intracerebroventricular administration of 500 ng prostaglandin E1 (PGE1) into a lateral cerebral ventricle. No drug was injected in control rats. The results show that NMA enhances the increases in firing rate, TIBAT and TC induced by PGE1. These findings indicate that an inhibitor of nitric oxide synthesis, such as NMA, increases the sympathetic and thermogenic responses to injection of PGE1.
Assuntos
Alprostadil/farmacologia , Inibidores Enzimáticos/farmacologia , Hipertermia Induzida , Óxido Nítrico Sintase/antagonistas & inibidores , Nitroarginina/farmacologia , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Marrom/inervação , Animais , Temperatura Corporal/efeitos dos fármacos , Temperatura Corporal/fisiologia , Estimulação Elétrica , Inibidores Enzimáticos/administração & dosagem , Injeções Intraventriculares , Masculino , Nitroarginina/administração & dosagem , Ratos , Ratos Sprague-Dawley , Sistema Nervoso Simpático/citologia , Sistema Nervoso Simpático/efeitos dos fármacos , Sistema Nervoso Simpático/fisiologiaRESUMO
The experiment described here tests the effect of intracerebroventricular (icv) injection of nitric oxide (NO) precursors, such as L-arginine (L-arg) and nitroprusside (NP), on the thermogenic changes induced by lesion of the lateral hypothalamus (LH). The firing rate of the nerves innervating interscapular brown adipose tissue (IBAT), along with IBAT and colonic temperatures (TIBAT and TC) were monitored in urethane-anaesthetized male Sprague-Dawley rats lesioned in the LH. These variables were measured before and after an icv injection of 4 mumol L-arg or 400 nmol NP. The same variables were also monitored in: a) lesioned rats with icv administration of saline; b) sham-lesioned animals with icv injection of L-arg or NP; c) sham-lesioned rats with icv injection of saline. The results show that L-arg or NP injection reduces the increases in firing rate. TIBAT and TC induced by LH lesion. These findings suggest that NO plays a key role in the thermogenic changes following LH lesion.
Assuntos
Regulação da Temperatura Corporal/efeitos dos fármacos , Hipotálamo/fisiologia , Óxido Nítrico/farmacologia , Animais , Arginina/farmacologia , Temperatura Corporal/efeitos dos fármacos , Injeções Intraventriculares , Masculino , Óxido Nítrico/fisiologia , Nitroprussiato/farmacologia , Ratos , Ratos Sprague-DawleyRESUMO
The aim of this experiment was to evaluate the effects of an intracerebroventricular (icv) injection of prostaglandin E1 (PGE1) on the sympathetic activation and the thermogenic changes in rats with acute lesions of the ventromedial hypothalamus (VMH). Four groups of six Sprague-Dawley male rats were anesthetized with ethyl-urethane. The firing rate of the sympathetic nerves innervating the interscapular brown adipose tissue (IBAT) and the colonic and IBAT temperatures were monitored both before and after one of the following treatments: 1) VMH lesion plus icv injection of PGE1 (500 ng); 2) VMH lesion plus icv injection of saline: 3) sham lesion plus icv injection of PGE1; and 4) sham lesion plus icv injection of saline. PGE1 induced an increase in the firing rate of IBAT nerves and the colonic and IBAT temperatures. These effects were reduced by VMH lesion. The findings indicate that acute lesions of the VMH reduce the effects of PGE1 and seem to suggest a possible role played by the VMH in the control of the sympathetic activation and the thermogenic changes during PGE1 hyperthermia.
Assuntos
Alprostadil/fisiologia , Regulação da Temperatura Corporal/fisiologia , Sistema Nervoso Simpático/fisiologia , Núcleo Hipotalâmico Ventromedial/fisiologia , Tecido Adiposo Marrom/inervação , Tecido Adiposo Marrom/fisiologia , Animais , Colo/fisiologia , Eletrofisiologia , Injeções Intraventriculares , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
Food intake and concentrations of glutamic (GLU) and aspartic (ASP) acids in the nucleus accumbens were monitored in male Sprague-Dawley rats fed a threonine free diet. These variables were measured before and after an intracerebroventricular injection of 20 nmole nitroprusside (NP), a non-enzymatic nitric oxide donor. The same variables were also monitored in: (a) rats fed a threonine free diet and injected with saline; (b) animals fed a standard diet and injected with nitroprusside; (c) rats fed a standard diet and injected with saline. The results showed that the threonine-free diet reduced food intake and GLU and ASP concentrations in the accumbens. NP reduced the hypophagia, but it did not change GLU and ASP levels in rats fed the threonine-free diet. In animals fed the standard diet, NP increased GLU and ASP concentration, and food intake. No change was found in the animals with saline injection. These findings suggest that nitric oxide reduces the hypophagia in the rats fed a threonine-free diet. The lack of increase in GLU and ASP concentration in the nucleus accumbens of the hypophagic rats indicates that NP acts on hypophagia independently by GLU and ASP.
Assuntos
Comportamento Alimentar/fisiologia , Óxido Nítrico/fisiologia , Treonina/administração & dosagem , Treonina/deficiência , Animais , Arginina/farmacologia , Ácido Aspártico/análise , Peso Corporal , Dieta , Ingestão de Alimentos/efeitos dos fármacos , Ingestão de Alimentos/fisiologia , Comportamento Alimentar/efeitos dos fármacos , Ácido Glutâmico/análise , Injeções Intraventriculares , Masculino , Nitroprussiato/farmacologia , Núcleo Accumbens/química , Núcleo Accumbens/fisiologia , Ratos , Ratos Sprague-Dawley , Reagentes de Sulfidrila/farmacologiaRESUMO
The firing rate of the neurons of the hypothalamic paraventricular nucleus, the temperatures of the interscapular brown adipose tissue and of the colon (TIBAT and Tc) were monitored in 24 urethane-anesthetized male Sprague-Dawley rats divided into four groups. These variables were measured before and after hippocampal injection of neostigmine (5x10(-7) mol) in the 1st and 2nd groups or of saline in the 3rd and 4th groups. The hippocampal injection was preceded by cortical spreading depression in the 1st and 3rd groups, while the cortical depression was not induced in the 2nd and 4th groups. The results show an increase of firing rate, TIBAT and Tc after neostigmine injection in the rats without cortical depression. Cortical spreading depression significantly reduces these enhancements. These findings demonstrate that: (1) the paraventricular nucleus plays a significant role in the hyperthermia induced by neostigmine injection into the hippocampus; and (2) the cerebral cortex is involved in the control of the paraventricular activity.
Assuntos
Depressão Alastrante da Atividade Elétrica Cortical/fisiologia , Hipocampo/efeitos dos fármacos , Neostigmina/farmacologia , Núcleo Hipotalâmico Paraventricular/fisiologia , Tecido Adiposo Marrom/fisiologia , Animais , Temperatura Corporal/efeitos dos fármacos , Temperatura Corporal/fisiologia , Colo/fisiologia , Eletrofisiologia , Injeções , Masculino , Neurônios/fisiologia , Núcleo Hipotalâmico Paraventricular/citologia , Ratos , Ratos Sprague-DawleyRESUMO
The firing rate of the nerves innervating interscapular brown adipose tissue (IBAT) and IBAT and colonic temperatures (TIBAT and TC were monitored in urethane-anaesthetized male Sprague-Dawley rats. These variables were measured for 40 min before (baseline values) and 40 min after a 4 micromoles L-arginine (L-arg) or 400 nmoles nitroprusside (NP) injection in a lateral cerebral ventricle and an intracerebroventricular administration of 500 ng prostaglandin E1 (PGE1). The same variables were monitored in other rats with L-arg or NP or PGE1 administration alone. No drug was injected in control rats. The results show that L-arg or NP injection reduces the increases in firing rate, TIBAT, Tc induced by PGE1. These findings suggest that nitric oxide is important in the control of thermogenic changes during the PGE1 hyperthermia.
Assuntos
Tecido Adiposo Marrom/efeitos dos fármacos , Alprostadil/farmacologia , Regulação da Temperatura Corporal/efeitos dos fármacos , Óxido Nítrico/farmacologia , Sistema Nervoso Simpático/efeitos dos fármacos , Potenciais de Ação/efeitos dos fármacos , Animais , Arginina/farmacologia , Injeções Intraventriculares , Masculino , Nitroprussiato/farmacologia , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos TestesRESUMO
The firing rate of the nerves innervating interscapular brown adipose tissue (IBAT), IBAT and colonic temperatures (TIBAT and Tc), heart rate, and oxygen (O2) consumption were monitored in urethane-anesthetized male Sprague-Dawley rats. These variables were measured for 40 min before (baseline values) and 40 min after a 56 ng muscimol injection in the posterior hypothalamus and an intracerebroventricular administration of 500 ng prostaglandin E1 (PGE1). The same variables were monitored in other rats with muscimol injection or PGE1 administration alone. No drug was injected in control rats. The results show that muscimol injection reduces the increases in firing rate, TIBAT, Tc, heart rate, O2 consumption induced by PGE1. These findings suggest that GABAergic tone in the posterior hypothalamus is important in the control of thermogenic changes induced by PGE1.
Assuntos
Alprostadil/farmacologia , Febre/prevenção & controle , Hipotálamo Posterior/fisiologia , Muscimol/farmacologia , Antagonistas de Prostaglandina/farmacologia , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/inervação , Alprostadil/administração & dosagem , Animais , Temperatura Corporal/efeitos dos fármacos , Colo/efeitos dos fármacos , Colo/fisiologia , Estimulação Elétrica , Febre/induzido quimicamente , Frequência Cardíaca/efeitos dos fármacos , Hipotálamo Posterior/anatomia & histologia , Injeções Intraventriculares , Masculino , Muscimol/administração & dosagem , Consumo de Oxigênio/efeitos dos fármacos , Ratos , Ratos Sprague-DawleyRESUMO
These experiments were designed to test the effect of procaine injection into the paraventricular nucleus on the sympathetic and thermogenic changes induced by frontal cortex stimulation. Oxygen consumption, firing rate of the sympathetic nerves to interscapular brown adipose tissue (IBAT), along with IBAT and colonic temperatures (T(IBAT) and T(C)) were monitored in fasted male Sprague-Dawley rats before and 25 min after an electrical stimulation of the frontal cortex. The same variables were monitored in rats with administration of procaine into the paraventricular nucleus. The results show that cortical stimulation raises oxygen consumption, sympathetic neuron firing rates, T(IBAT), and T(C). This increase is reduced by procaine injection. These findings suggest that the paraventricular nucleus plays a key role in the sympathetic and thermogenic changes induced by cortical stimulation.
Assuntos
Anestésicos Locais/farmacologia , Temperatura Corporal/efeitos dos fármacos , Núcleo Hipotalâmico Paraventricular/fisiologia , Procaína/farmacologia , Sistema Nervoso Simpático/fisiologia , Tecido Adiposo Marrom/fisiologia , Animais , Química Encefálica/efeitos dos fármacos , Colo/inervação , Colo/fisiologia , Lobo Frontal/citologia , Lobo Frontal/efeitos dos fármacos , Lobo Frontal/fisiologia , Masculino , Vias Neurais , Consumo de Oxigênio/fisiologia , Núcleo Hipotalâmico Paraventricular/citologia , Núcleo Hipotalâmico Paraventricular/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Sistema Nervoso Simpático/citologia , Sistema Nervoso Simpático/efeitos dos fármacosRESUMO
The aim of this experiment was to evaluate the effects of ventromedial hypothalamus lesions on the thermogenic changes that follow food intake. Four groups of six Sprague-Dawley male rats were used. Under anesthesia with pentobarbital, the animals in the first and second groups received lesions at the ventromedial hypothalamus, and animals in the third and fourth groups received sham lesions. Body weight and food intake were monitored daily until the experimental procedure began. Twenty days after lesion, oxygen consumption, firing rate of sympathetic nerves to interscapular brown adipose tissue (IBAT), and IBAT temperature were monitored for 45 min both before and after 5 g food intake in 24 h fasted rats from the first and third groups. The same variables were measured in the animals of the second and fourth groups 50 days after receiving the lesions. Lesion placements were histologically verified. The results showed that lesions produced hyperphagia and obesity. Firing rate of nerves to IBAT, IBAT temperature, and oxygen consumption increased after food intake in sham-lesioned rats. This increase was significantly reduced by the lesion at both the 20- and 50-day time points. These findings indicate that the ventromedial hypothalamus controls postingestional activation of sympathetic discharge to IBAT. The reduction of postingestional thermogenesis could be involved in the development of obesity induced by lesion of the ventromedial hypothalamus.
Assuntos
Regulação da Temperatura Corporal/fisiologia , Período Pós-Prandial/fisiologia , Núcleo Hipotalâmico Ventromedial/fisiologia , Tecido Adiposo Marrom/fisiologia , Animais , Peso Corporal/fisiologia , Mapeamento Encefálico , Ingestão de Alimentos/fisiologia , Masculino , Consumo de Oxigênio/fisiologia , Ratos , Ratos Sprague-Dawley , Sistema Nervoso Simpático/fisiologiaRESUMO
Interscapular brown adipose tissue (IBAT) activity is controlled by sympathetic nervous system, and factors that influence thermogenesis appear to be centrally connected to the sympathetic outflow to IBAT. Cold exposure produces a rise in BAT temperature, which is associated with an increased thyroid activity, elevated serum levels of 3,5,3'-triiodothyronine (T3), and an increased rate of T3 production. This study evaluated the effect of swimming training on 5'-triiodothyronine deiodinase (5'-D) activity in IBAT under normal environmental conditions and after short (30 min) cold exposure (TST stimulation test). 5'-D activity is lower in trained rats at basal condition, and TST increases 5'-D in IBAT of both untrained and trained rats. However, this increase is lower in trained rats. Training reduces the deiodinating activity in normal environmental conditions as well as after short cold exposure. Probably, other compensatory mechanisms of heat production are active in trained rodents.
Assuntos
Tecido Adiposo Marrom/enzimologia , Regulação da Temperatura Corporal/fisiologia , Temperatura Baixa , Iodeto Peroxidase/metabolismo , Animais , Ingestão de Alimentos/fisiologia , Masculino , Consumo de Oxigênio/fisiologia , Ratos , Ratos Sprague-Dawley , Tiroxina/sangue , Tri-Iodotironina/sangueRESUMO
This experiment tested the effects of an intracerebroventricular injection of prostaglandin E1 on the sympathetic activation and the thermogenic changes in rats with ibotenate lesions of the ventromedial hypothalamus. Under pentobarbital anesthesia, twelve Sprague-Dawley male rats were lesioned bilaterally in the ventromedial hypothalamus with an injection of ibotenic acid (30 nmol into each side). Sham lesions were carried out in other twelve control rats. After 48 h, all animals were anesthetized with ethyl-urethane. The firing rate of the sympathetic nerves innervating the interscapular brown adipose tissue and the colonic and interscapular brown adipose tissue temperatures were monitored before and after an intracerebroventricular injection of prostaglandin E1 (500 ng) or saline. Prostaglandin E1 induced an increase in the firing rate of sympathetic nerves and the colonic and interscapular brown adipose tissue temperatures. These effects were reduced by the ventromedial hypothalamic lesion. Since ibotenic acid destroys cell bodies, the findings indicate that neurons of the ventromedial hypothalamus play a considerable role in the control of sympathetic activation and the thermogenic changes during prostaglandin E1 hyperthermia.
Assuntos
Alprostadil/farmacologia , Febre/fisiopatologia , Vasodilatadores/farmacologia , Núcleo Hipotalâmico Ventromedial/patologia , Núcleo Hipotalâmico Ventromedial/fisiopatologia , Tecido Adiposo Marrom/fisiologia , Animais , Agonistas de Aminoácidos Excitatórios , Febre/induzido quimicamente , Ácido Ibotênico , Injeções Intraventriculares , Masculino , Pirogênios/farmacologia , Ratos , Ratos Sprague-Dawley , Simpatectomia , Sistema Nervoso Simpático/efeitos dos fármacos , Sistema Nervoso Simpático/fisiologiaRESUMO
The aim of the present study was to examine the influence of a high carbohydrate diet and the level of aerobic capacity on running performance during a 25-km treadmill time trial. The study used a 2*2 design with the factors being training and diet composition. We divided the athletes in 4 groups: 1. Trained athletes with carbohydrate loading (CHO1); 2. Trained athletes without carbohydrate loading (C1); 3. Untrained athletes with carbohydrate loading (CHO2); 4. Untrained athletes without carbohydrate loading (C2). The carbohydrate loading was effected with confectionery. Performance time, running speed, blood glucose and blood lactate concentrations were evaluated during two 25-km treadmill time trial (trial 1 and trial 2) separated by 7 days in which two groups (CHO1 and CHO2) had a carbohydrate loading. The results showed that the athletes with lower level of aerobic capacity had better performance time after carbohydrate loading. They ran faster and had a higher glucose and lactate concentrations in the last 5 km during trial 2. There were no significant differences in the other groups. In conclusion, we can assert that dietary carbohydrate loading can improve running performance and that confectionery can be used as an effective means of supplementing the normal carbohydrate intake in preparation for endurance competitions. But the improvement depends on some factors such as the distance and the level of aerobic capacity.
Assuntos
Carboidratos da Dieta/farmacologia , Exercício Físico/fisiologia , Corrida/fisiologia , Adulto , Humanos , Masculino , Estado Nutricional , Aptidão Física/fisiologiaRESUMO
This review focuses on recent advances in the understanding of lipid crystallisation at or in the vicinity of an interface in emulsified systems and the consequences regarding stability, structure and thermal behaviour. Amphiphilic molecules such as emulsifiers are preferably adsorbed at the interface. Such molecules are known for their ability to interact with triglycerides under certain conditions. In the same manner that inorganic crystals grown on an organic matrix see their nucleation, morphology and structure controlled by the underlying matrix, recent studies report a templating effect linked to the presence of emulsifiers at the oil/water interface. Emulsifiers affect fat crystallisation and fat crystal behaviour in numerous ways, acting as impurities seeding nucleation and, in some cases, retarding or enhancing polymorphic transitions towards more stable forms. This understanding is of crucial importance for the design of stable structures within emulsions, regardless of whether the system is oil or water continuous. In this paper, crystallisation mechanisms are briefly described, as well as recent technical advances that allow the study of crystallisation and crystal forms. Indeed, the study of the interface and of its effect on lipid crystallisation in emulsions has been limited for a long time by the lack of in-situ investigative techniques. This review also highlights reported interfacial effects in food and pharmaceutical emulsion systems. These effects are strongly linked to the presence of emulsifiers at the interface and their effects on crystallisation kinetics, and crystal morphology and stability.
Assuntos
Temperatura Baixa , Metabolismo Energético/fisiologia , Sistema Hipotálamo-Hipofisário/fisiologia , Iodeto Peroxidase/metabolismo , Glândula Tireoide/fisiologia , Tecido Adiposo Marrom/metabolismo , Animais , Masculino , Estimulação Física , Ratos , Ratos Sprague-Dawley , Sistema Nervoso Simpático/fisiologiaRESUMO
We studied the effects of peritendinous Achilles tendon injections of prostaglandin E1 (PGE1) on the Achilles tendon of rats. Five groups of Sprague-Dawley rats (n = 24 each) were studied. Groups 1 to 4 received weekly peritendinous injections. In group 1, one side was injected with 800 ng of PGE1 in 0.5 ml of 0.9% NaCl and the contralateral side was injected with 0.5 ml of 0.9% NaCl. In group 2, one side was injected with 800 ng of PGE1. In group 3, one side was injected with 0.5 ml of 0.9% NaCl. In group 4, a syringe needle was inserted in the peritenon unilaterally, but no substances were administered. In groups 2, 3, and 4, the contralateral tendon was used as the control. In group 5, treatment was not administered. Eight rats in each group were killed at each time point, after 7, 21, and 35 days of treatment. On day 7, values for average water content and average wet weight of the tendons treated with PGE1 were significantly higher than those in the control tendons (analysis of variance [ANOVA]; P = 0.02), with a histological picture of acute inflammation. On day 21, approximately half of the PGE1-treated tendons showed fibrosis of the paratenon, with adhesions and intra-tendinous degeneration, with the other half still showing a picture of acute inflammation. On day 35, all of the PGE1-treated tendons showed fibrosis of the paratenon, with adhesions and intra-tendinous degeneration. At all time points, there was no evidence of pathology in the tendons that had not received PGE1. Sham peritendinous injections and injections of normal saline did not produce inflammation in the Achilles tendons. Initially, local administration of PGE1 produced acute inflammation of the tendon and its surrounding tissues. Prolonged PGE1 administration produced peri- and intra-tendinous degeneration, providing a cheap, reproducible model of Achilles tendinopathy, which would allow studies of the effects of conservative and surgical management of the condition.
Assuntos
Tendão do Calcâneo/efeitos dos fármacos , Alprostadil/farmacologia , Modelos Animais de Doenças , Tendinopatia/induzido quimicamente , Tendão do Calcâneo/patologia , Análise de Variância , Animais , Distribuição de Qui-Quadrado , Injeções , Masculino , Ratos , Ratos Sprague-Dawley , Estatísticas não Paramétricas , Tendinopatia/patologiaRESUMO
This experiment tests the effect of intracerebroventricular (icv) injection of lysine acetylsalicylate on the sympathetic and thermogenic changes induced by lesion of the lateral hypothalamus (LH). The firing rate of the nerves innervating interscapular brown adipose tissue (IBAT), along with IBAT and colonic temperatures (TIBAT and Tc) were monitored in urethane-anaesthetized male Sprague-Dawley rats lesioned in the LH. These variables were measured before and after an icv injection of 1mg lysine acetylsalicylate. The same variables were also monitored in: a) lesioned rats with icv administration of saline; b) sham-lesioned animals with icv injection of lysine acetylsalicylate; c) sham-lesioned rats with icv injection of saline. In an additional experiment, the same variables were monitored after an icv injection of lysine acetylsalicylate or saline in rats with LH lesion performed 48 h before the icv injection. The results show that lysine acetylsalicylate injection reduces the increases in firing rate, TIBAT and Tc induced by LH lesion. These findings suggest that cerebral prostaglandin synthesis plays a key role in the sympathetic and thermogenic changes following LH lesion.