Stress during the neonatal period leads to a large number of behavioral and biochemical alteratio... more Stress during the neonatal period leads to a large number of behavioral and biochemical alterations in adult life. The aim of this study is to verify the effects of handling and tactile stimulation during the first 10 days of life on feeding behavior in adult rats. Litters were divided into (1). intact; (2). handled (10 min/day); and (3). handled and tactile stimulated (10 min/day). Procedures were performed on Days 1-10 after birth. When adults, rats were tested for ingestion of sweet and savory snacks. We also measured body weight, ingestion of standard lab chow, and consumption of water and 1% glucose and 1.5% NaCl solutions. Stressed rats (handling and handling+tactile stimulation groups) consumed more sweet (two-way ANOVA, P=.008) or savory snacks (P=.001) than intact ones. This effect was observed in males and females. There were no differences in body weight, ingestion of standard lab chow, water, or in the ingestion of sweetened or salty solutions between groups. The same animals were tested later in life (15 months of age), and the effect was still evident. We suggest that handling during the neonatal period leads to alterations in the CNS of rats, causing an increased ingestion of palatable food in adult life, and this alteration probably persists throughout the whole life.
Monoaminergic systems are important modulators of the responses to stress. Stress may influence f... more Monoaminergic systems are important modulators of the responses to stress. Stress may influence feeding behavior, and the involvement of monoamines in the control of food intake is well recognized. We investigated the effects induced by chronic-restraint stress, 1 h a day, for 40 days, on eating behavior and on monoamines in distinct brain structures. Increased consumption of sweet pellets, and not of peanuts, was observed. Dopamine (DA), serotonin (5-HT), and their metabolites were measured by HPLC-EC. After chronic restraint, the results observed were decreased 5-HT in hippocampus, with increased 5-HIAA/5-HT; decreased 5-HIAA levels in cortex; reduction in DA in hippocampus, and increased levels in amygdala and hypothalamus; HVA increased in cortex, as well as HVA/DA ratio, while DOPAC/DA decreased. HVA decreased in hypothalamus, as well as HVA/DA, and DOPAC/DA and HVA/DA decreased in the amygdala. These results suggest that restraint stress differentially affects the activity of ...
Esta atividade fez parte do Projeto de Extensao"DEscobrindo a Ciencia na EScola". O tra... more Esta atividade fez parte do Projeto de Extensao"DEscobrindo a Ciencia na EScola". O trabalho foi realizado com alunos de 5a serie, utilizando a aplicacao do metodo cientifico para abordagem de conteudos de botânica (plantas medicinais) relacionados com o cotidiano. O objetivo do trabalho foi estimular a busca de informacoes entre os familiares por meio da discussao sobre a utilizacao de plantas medicinais. A atividade foi dividida em cinco momentos. O momento inicial foi constituido pela coleta de informacoes junto as familias dos educandos. Apos, as informacoes eram utilizadas para discussao em sala de aula com colegas de grupo e cofeccao de cartazes autoexplicativos. Estes foram apresenatados em sala de aula para os demais colegas. Posteiormente os mesmos foram expostos na escola para divulgacao perante aos demais colegas. Verificamos que 89% dos alunos gostou da atividade e se sentiram motivados para tal. Esse resultado corrobora com dados da literatura que demonstram a...
Monoaminergic systems are important modulators of the responses to stress. Stress may influence f... more Monoaminergic systems are important modulators of the responses to stress. Stress may influence feeding behavior, and the involvement of monoamines in the control of food intake is well recognized. We investigated the effects induced by chronic-restraint stress, 1 h a day, for 40 days, on eating behavior and on monoamines in distinct brain structures. Increased consumption of sweet pellets, and not of peanuts, was observed. Dopamine (DA), serotonin (5-HT), and their metabolites were measured by HPLC-EC. After chronic restraint, the results observed were decreased 5-HT in hippocampus, with increased 5-HIAA/5-HT; decreased 5-HIAA levels in cortex; reduction in DA in hippocampus, and increased levels in amygdala and hypothalamus; HVA increased in cortex, as well as HVA/DA ratio, while DOPAC/DA decreased. HVA decreased in hypothalamus, as well as HVA/DA, and DOPAC/DA and HVA/DA decreased in the amygdala. These results suggest that restraint stress differentially affects the activity of central dopaminergic and serotonergic neurons, and this may be related to the effects observed in eating behavior.
Stress-induced alterations in feeding behavior are sexually dimorphic and have been related to ch... more Stress-induced alterations in feeding behavior are sexually dimorphic and have been related to changes in monoamine levels. Fluoxetine is commonly used as an antidepressant and has also been suggested as an adjunct to other strategies to treat obese individuals. Leptin may interact with stress hormones and with the brain serotonergic system, possibly affecting the feeding behavior of stressed rats. The aim of this study is to evaluate the interaction between chronic fluoxetine treatment and leptin levels in adult female Wistar rats submitted to chronic variable stress. After 30 days of stress, control and stressed groups were subdivided into two groups that received daily injections of vehicle or fluoxetine (8 mg/kg, i.p.). Body weight was evaluated before and after fluoxetine treatment. The animals gained weight with time, signifying that there is a difference in weight gain over time when fluoxetine-treated animals are, or not, subjected to the stress model. Both fluoxetine and stress induced a decrease in sweet food consumption. On the 60th day of fluoxetine treatment, leptin levels were decreased in fluoxetine-treated animals and there was no effect of stress. We conclude that chronic fluoxetine treatment induced a decreased intake of sweet food, as well as a reduction in leptin levels, and that this result could represent a compensatory response to reduced food intake rather than a direct anorectic mechanism. No interaction with chronic stress was observed.
Exposure to stress may cause either an increase or a decrease in food intake. Behavioral and phys... more Exposure to stress may cause either an increase or a decrease in food intake. Behavioral and physiological responses to stress, including alterations in feeding behavior, are sexually dimorphic. This study aimed to evaluate the interaction between estradiol levels and chronic variate stress on the intake of sweet food and on serum levels of leptin, a hormone secreted by the adipose cells with a role in the regulation of body weight. Adult female Wistar rats were used. After ovariectomy, the animals received estradiol replacement (or oil) subcutaneously. Rats were then divided in controls and stressed (submitted to 30 days of variate stress). Consumption of sweet food and of serum leptin was measured. Although animals receiving estradiol replacement presented smaller weight gain, they showed an increased consumption of sweet food. Chronic variate stress decreased sweet food intake at 30, but not at 20, days of treatment. Estradiol replacement in the stressed group prevented both the reduction observed in sweet food intake and the increase in leptin levels. These results suggest that there is an interaction between chronic stress and estradiol replacement in feeding behavior concerning sweet food consumption, and this interaction may be related to altered leptin levels.
Breast cancer is one of the common tumors occurring in woman and despite treatment, the prognosti... more Breast cancer is one of the common tumors occurring in woman and despite treatment, the prognostic is poor. Genistein, a soy isoflavone, has been reported to have chemopreventive\chemotherapeutic potential in multiple tumor types. Here, we investigated the genistein antiproliferative effect in MCF-7 breast cancer, underlying the molecular mechanisms involved in this effect. MCF-7 cancer and CCD1059sK fibroblast cells were treated with estradiol (10 nM) or genistein (0.01-100 μM) for 24, 48, and 72 h and the cell proliferation was investigated by MTT; membrane cell permeability was evaluated by LDH and PI incorporation; apoptosis was investigated by externalization of phosphatidylserine by FACS; and presence of autophagy was detected by LC3A/B immunostaining. The expression of apoptotic proteins and antioxidant enzymes was evaluated by qPCR. The results demonstrate that genistein (100 μM) for 72 h of treatment selectively reduced MCF-7 cell proliferation independent of estrogen receptor activation, while no cytotoxicity was observed in fibroblast cells. Further experiments showed that genistein induced phosphatidylserine externalization and LC3A/B immunopositivity in MCF-7 cells, indicating apoptosis and autophagy cell death. Genistein increased in three times proapoptotic BAX/Bcl-2 ratio and promoted a parallel downregulation of 20 times of antiapoptotic survivin. In addition, genistein promoted a decrease of 5.5, 9.3, and 3.6 times of MnSOD, CuZnSOD, and TrxR mRNA expression, respectively, while the GPx expression was increased by 6.5 times. These results suggest that the antitumor effect of genistein involved the modulation of antioxidant enzyme and apoptotic signaling expression, which resulted in apoptosis and progression of autophagy.
Brazilian Journal of Medical and Biological Research, 1999
The present study investigated the effect of repeated stress applied to female rats on memory eva... more The present study investigated the effect of repeated stress applied to female rats on memory evaluated by three behavioral tasks: two-way shuttle avoidance, inhibitory avoidance and habituation to an open field. Repeated stress had different effects on rat behavior when different tasks were considered. In the two-way active avoidance test the stressed animals presented memory of the task, but their memory scores were impaired when compared to all other groups. In the habituation to the open field, only the control group showed a significant difference in the number of rearings between training and testing sessions, which is interpreted as an adequate memory of the task. In the handled and chronically stressed animals, on the other hand, no memory was observed, suggesting that even a very mild repeated stress would be enough to alter habituation to this task. The performance in the inhibitory avoidance task presented no significant differences between groups. The findings suggest th...
It has previously been reported that exposure to repeated restraint stress induces hyperalgesia i... more It has previously been reported that exposure to repeated restraint stress induces hyperalgesia in male rats, an effect that was not observed in females. The aim of the present study was to investigate the effects of chronic variable stress over 40days on nociception threshold indexed by tail-flick latency in male and female adult rats. The results showed different behavior in chronically stressed animals when compared to the control group: male rats showed a decrease in tail-flick latency while females presented an increase in this parameter. For female rats this effect was independent of the phase of the estrous cycle. Several sources of data indicate that behavioral and physiological responses to stress are sexually dimorphic, including in nociception, and the estrous cycle appears to be a factor that influences opioid analgesia in female. These effects are modulated by the strain and conditions of nociception assay. Additional studies concerning the mechanisms involved in the hyperalgesic response in males and the differences on nociceptive response in females chronically exposed to stress are needed.
Stress during the neonatal period leads to a large number of behavioral and biochemical alteratio... more Stress during the neonatal period leads to a large number of behavioral and biochemical alterations in adult life. The aim of this study is to verify the effects of handling and tactile stimulation during the first 10 days of life on feeding behavior in adult rats. Litters were divided into (1). intact; (2). handled (10 min/day); and (3). handled and tactile stimulated (10 min/day). Procedures were performed on Days 1-10 after birth. When adults, rats were tested for ingestion of sweet and savory snacks. We also measured body weight, ingestion of standard lab chow, and consumption of water and 1% glucose and 1.5% NaCl solutions. Stressed rats (handling and handling+tactile stimulation groups) consumed more sweet (two-way ANOVA, P=.008) or savory snacks (P=.001) than intact ones. This effect was observed in males and females. There were no differences in body weight, ingestion of standard lab chow, water, or in the ingestion of sweetened or salty solutions between groups. The same animals were tested later in life (15 months of age), and the effect was still evident. We suggest that handling during the neonatal period leads to alterations in the CNS of rats, causing an increased ingestion of palatable food in adult life, and this alteration probably persists throughout the whole life.
Monoaminergic systems are important modulators of the responses to stress. Stress may influence f... more Monoaminergic systems are important modulators of the responses to stress. Stress may influence feeding behavior, and the involvement of monoamines in the control of food intake is well recognized. We investigated the effects induced by chronic-restraint stress, 1 h a day, for 40 days, on eating behavior and on monoamines in distinct brain structures. Increased consumption of sweet pellets, and not of peanuts, was observed. Dopamine (DA), serotonin (5-HT), and their metabolites were measured by HPLC-EC. After chronic restraint, the results observed were decreased 5-HT in hippocampus, with increased 5-HIAA/5-HT; decreased 5-HIAA levels in cortex; reduction in DA in hippocampus, and increased levels in amygdala and hypothalamus; HVA increased in cortex, as well as HVA/DA ratio, while DOPAC/DA decreased. HVA decreased in hypothalamus, as well as HVA/DA, and DOPAC/DA and HVA/DA decreased in the amygdala. These results suggest that restraint stress differentially affects the activity of ...
Esta atividade fez parte do Projeto de Extensao"DEscobrindo a Ciencia na EScola". O tra... more Esta atividade fez parte do Projeto de Extensao"DEscobrindo a Ciencia na EScola". O trabalho foi realizado com alunos de 5a serie, utilizando a aplicacao do metodo cientifico para abordagem de conteudos de botânica (plantas medicinais) relacionados com o cotidiano. O objetivo do trabalho foi estimular a busca de informacoes entre os familiares por meio da discussao sobre a utilizacao de plantas medicinais. A atividade foi dividida em cinco momentos. O momento inicial foi constituido pela coleta de informacoes junto as familias dos educandos. Apos, as informacoes eram utilizadas para discussao em sala de aula com colegas de grupo e cofeccao de cartazes autoexplicativos. Estes foram apresenatados em sala de aula para os demais colegas. Posteiormente os mesmos foram expostos na escola para divulgacao perante aos demais colegas. Verificamos que 89% dos alunos gostou da atividade e se sentiram motivados para tal. Esse resultado corrobora com dados da literatura que demonstram a...
Monoaminergic systems are important modulators of the responses to stress. Stress may influence f... more Monoaminergic systems are important modulators of the responses to stress. Stress may influence feeding behavior, and the involvement of monoamines in the control of food intake is well recognized. We investigated the effects induced by chronic-restraint stress, 1 h a day, for 40 days, on eating behavior and on monoamines in distinct brain structures. Increased consumption of sweet pellets, and not of peanuts, was observed. Dopamine (DA), serotonin (5-HT), and their metabolites were measured by HPLC-EC. After chronic restraint, the results observed were decreased 5-HT in hippocampus, with increased 5-HIAA/5-HT; decreased 5-HIAA levels in cortex; reduction in DA in hippocampus, and increased levels in amygdala and hypothalamus; HVA increased in cortex, as well as HVA/DA ratio, while DOPAC/DA decreased. HVA decreased in hypothalamus, as well as HVA/DA, and DOPAC/DA and HVA/DA decreased in the amygdala. These results suggest that restraint stress differentially affects the activity of central dopaminergic and serotonergic neurons, and this may be related to the effects observed in eating behavior.
Stress-induced alterations in feeding behavior are sexually dimorphic and have been related to ch... more Stress-induced alterations in feeding behavior are sexually dimorphic and have been related to changes in monoamine levels. Fluoxetine is commonly used as an antidepressant and has also been suggested as an adjunct to other strategies to treat obese individuals. Leptin may interact with stress hormones and with the brain serotonergic system, possibly affecting the feeding behavior of stressed rats. The aim of this study is to evaluate the interaction between chronic fluoxetine treatment and leptin levels in adult female Wistar rats submitted to chronic variable stress. After 30 days of stress, control and stressed groups were subdivided into two groups that received daily injections of vehicle or fluoxetine (8 mg/kg, i.p.). Body weight was evaluated before and after fluoxetine treatment. The animals gained weight with time, signifying that there is a difference in weight gain over time when fluoxetine-treated animals are, or not, subjected to the stress model. Both fluoxetine and stress induced a decrease in sweet food consumption. On the 60th day of fluoxetine treatment, leptin levels were decreased in fluoxetine-treated animals and there was no effect of stress. We conclude that chronic fluoxetine treatment induced a decreased intake of sweet food, as well as a reduction in leptin levels, and that this result could represent a compensatory response to reduced food intake rather than a direct anorectic mechanism. No interaction with chronic stress was observed.
Exposure to stress may cause either an increase or a decrease in food intake. Behavioral and phys... more Exposure to stress may cause either an increase or a decrease in food intake. Behavioral and physiological responses to stress, including alterations in feeding behavior, are sexually dimorphic. This study aimed to evaluate the interaction between estradiol levels and chronic variate stress on the intake of sweet food and on serum levels of leptin, a hormone secreted by the adipose cells with a role in the regulation of body weight. Adult female Wistar rats were used. After ovariectomy, the animals received estradiol replacement (or oil) subcutaneously. Rats were then divided in controls and stressed (submitted to 30 days of variate stress). Consumption of sweet food and of serum leptin was measured. Although animals receiving estradiol replacement presented smaller weight gain, they showed an increased consumption of sweet food. Chronic variate stress decreased sweet food intake at 30, but not at 20, days of treatment. Estradiol replacement in the stressed group prevented both the reduction observed in sweet food intake and the increase in leptin levels. These results suggest that there is an interaction between chronic stress and estradiol replacement in feeding behavior concerning sweet food consumption, and this interaction may be related to altered leptin levels.
Breast cancer is one of the common tumors occurring in woman and despite treatment, the prognosti... more Breast cancer is one of the common tumors occurring in woman and despite treatment, the prognostic is poor. Genistein, a soy isoflavone, has been reported to have chemopreventive\chemotherapeutic potential in multiple tumor types. Here, we investigated the genistein antiproliferative effect in MCF-7 breast cancer, underlying the molecular mechanisms involved in this effect. MCF-7 cancer and CCD1059sK fibroblast cells were treated with estradiol (10 nM) or genistein (0.01-100 μM) for 24, 48, and 72 h and the cell proliferation was investigated by MTT; membrane cell permeability was evaluated by LDH and PI incorporation; apoptosis was investigated by externalization of phosphatidylserine by FACS; and presence of autophagy was detected by LC3A/B immunostaining. The expression of apoptotic proteins and antioxidant enzymes was evaluated by qPCR. The results demonstrate that genistein (100 μM) for 72 h of treatment selectively reduced MCF-7 cell proliferation independent of estrogen receptor activation, while no cytotoxicity was observed in fibroblast cells. Further experiments showed that genistein induced phosphatidylserine externalization and LC3A/B immunopositivity in MCF-7 cells, indicating apoptosis and autophagy cell death. Genistein increased in three times proapoptotic BAX/Bcl-2 ratio and promoted a parallel downregulation of 20 times of antiapoptotic survivin. In addition, genistein promoted a decrease of 5.5, 9.3, and 3.6 times of MnSOD, CuZnSOD, and TrxR mRNA expression, respectively, while the GPx expression was increased by 6.5 times. These results suggest that the antitumor effect of genistein involved the modulation of antioxidant enzyme and apoptotic signaling expression, which resulted in apoptosis and progression of autophagy.
Brazilian Journal of Medical and Biological Research, 1999
The present study investigated the effect of repeated stress applied to female rats on memory eva... more The present study investigated the effect of repeated stress applied to female rats on memory evaluated by three behavioral tasks: two-way shuttle avoidance, inhibitory avoidance and habituation to an open field. Repeated stress had different effects on rat behavior when different tasks were considered. In the two-way active avoidance test the stressed animals presented memory of the task, but their memory scores were impaired when compared to all other groups. In the habituation to the open field, only the control group showed a significant difference in the number of rearings between training and testing sessions, which is interpreted as an adequate memory of the task. In the handled and chronically stressed animals, on the other hand, no memory was observed, suggesting that even a very mild repeated stress would be enough to alter habituation to this task. The performance in the inhibitory avoidance task presented no significant differences between groups. The findings suggest th...
It has previously been reported that exposure to repeated restraint stress induces hyperalgesia i... more It has previously been reported that exposure to repeated restraint stress induces hyperalgesia in male rats, an effect that was not observed in females. The aim of the present study was to investigate the effects of chronic variable stress over 40days on nociception threshold indexed by tail-flick latency in male and female adult rats. The results showed different behavior in chronically stressed animals when compared to the control group: male rats showed a decrease in tail-flick latency while females presented an increase in this parameter. For female rats this effect was independent of the phase of the estrous cycle. Several sources of data indicate that behavioral and physiological responses to stress are sexually dimorphic, including in nociception, and the estrous cycle appears to be a factor that influences opioid analgesia in female. These effects are modulated by the strain and conditions of nociception assay. Additional studies concerning the mechanisms involved in the hyperalgesic response in males and the differences on nociceptive response in females chronically exposed to stress are needed.
Uploads
Papers by G.d Gamaro