Rearing is an exploratory behavior induced by novelty, such as exposure to an open field. Stimulation of certain brain regions, including the hippocampus, induces both rearing and clonic convulsions. Brain excitabilit...Rearing is an exploratory behavior induced by novelty, such as exposure to an open field. Stimulation of certain brain regions, including the hippocampus, induces both rearing and clonic convulsions. Brain excitability is controlled by gamma-aminobutyric acid (GABA) inhibitory neurotransmission through its ionotropic GABAA/allosteric benzodiazepine site. Drugs that decrease GABAA receptor fast inhibitory neurotransmission induce clonic convulsions and rearing when injected into the hippocampus. Therefore, individual differences in rearing behavior may be related to the susceptibility to clonic convulsions, which could involve differences in brain excitability controlled by GABAA/allosteric benzodiazepine site receptors. Adult, male Wistar rats were divided into high- (HR) and low-rearing (LR) groups based on the number of rearings in the open field test. Groups of HR and LR rats were challenged with convulsant drugs that antagonize GABA neurotransmission via different mechanisms of action (3-mercaptopropionic acid, a glutamate decarboxilase inhibitor;bicuculline, a GABAA receptor antagonist;pentylenetetrazol and picrotoxin, both GABAA receptor chloride channel blockers and DMCM, a benzodiazepine inverse agonist). The convulsant doses that induced 50% of clonic convulsions were determined for each drug. The LR rats had a higher susceptibility (a lower convulsant dose 50%) to clonic convulsions induced by DMCM than the HR rats, but there were no differences between the groups in the susceptibility to tonic convulsions induced by the same drug. There were no significant differences in the convulsant dose 50% for clonic convulsions between the groups for all other drugs injected. In another experiment, additional HR and LR rats were injected with a sedative-hypnotic dose of diazepam, which caused a significantly higher hypnotic effect (sleeping-time) in the LR rats than in the HR rats. The LR group was also shown to have a significantly lower density of [3H]-Flunitrazepam bound to the GABAA receptor in hippocampal membranes. Our data suggest that inter-individual differences in rearing are related, at least in part, to the GABA inhibitory neurotransmission controlled by the benzodiazepine allosteric site in the GABAA receptor.展开更多
Background The first year of attending university induces a stressful experience for many college students. The experience exposes these students to challenging circumstances and raises expectations, which consequentl...Background The first year of attending university induces a stressful experience for many college students. The experience exposes these students to challenging circumstances and raises expectations, which consequently increases the risk of psychiatric disorders and may exacerbate pre-existing problems. This study was designed to explore the risk factors of psychological symptoms among freshmen in China. Methods A three-year follow-up study was designed in a sample of Chinese college freshmen. To set up the baseline interviews, subjects from 25 high schools in Beijing were interviewed during the first year in high school. Three years later, we followed up with the 1547 students from 15 of the previously-selected 25 high schools after they had entered universities. Association between potential risk factors and the occurrence of psychological symptoms measured by the Symptoms Check List-90 was evaluated in unconditional logistic regression models with Wald test. Results Among the 1547 interviewed college freshmen in the study, 120 students （7.8%） manifested at least one psychological symptom. Personality dysfunction （OR=3.655, 95% CI 1.967-6.793）, parental rejection （OR=2.619, 95% CI 1.544-4.442）, age 〉 20 （OR=2.578, 95% CI 1.227-5.418）, disfavored university （OR=2.054, 95% CI 1.376-3.066）, non- first-choice academic major （OR=1.887, 95% CI 1.255-2.837） and no orientation （OR=1.739, 95% CI 1.025-2.951） were determined to be the risk factors of psychological symptoms among the college freshmen in China. Conclusions Psychological symptoms of college freshmen are associated with personality traits, parental rearing behavior and study environment. Therefore, it is important to pay attention to changes in mental health as students enter or decide on colleges and increase education geared towards mental health issues for students in high school and universities in China.展开更多
基金Associacao Fundo de In- centivo a Psicofarmacologia (AFIP)
文摘Rearing is an exploratory behavior induced by novelty, such as exposure to an open field. Stimulation of certain brain regions, including the hippocampus, induces both rearing and clonic convulsions. Brain excitability is controlled by gamma-aminobutyric acid (GABA) inhibitory neurotransmission through its ionotropic GABAA/allosteric benzodiazepine site. Drugs that decrease GABAA receptor fast inhibitory neurotransmission induce clonic convulsions and rearing when injected into the hippocampus. Therefore, individual differences in rearing behavior may be related to the susceptibility to clonic convulsions, which could involve differences in brain excitability controlled by GABAA/allosteric benzodiazepine site receptors. Adult, male Wistar rats were divided into high- (HR) and low-rearing (LR) groups based on the number of rearings in the open field test. Groups of HR and LR rats were challenged with convulsant drugs that antagonize GABA neurotransmission via different mechanisms of action (3-mercaptopropionic acid, a glutamate decarboxilase inhibitor;bicuculline, a GABAA receptor antagonist;pentylenetetrazol and picrotoxin, both GABAA receptor chloride channel blockers and DMCM, a benzodiazepine inverse agonist). The convulsant doses that induced 50% of clonic convulsions were determined for each drug. The LR rats had a higher susceptibility (a lower convulsant dose 50%) to clonic convulsions induced by DMCM than the HR rats, but there were no differences between the groups in the susceptibility to tonic convulsions induced by the same drug. There were no significant differences in the convulsant dose 50% for clonic convulsions between the groups for all other drugs injected. In another experiment, additional HR and LR rats were injected with a sedative-hypnotic dose of diazepam, which caused a significantly higher hypnotic effect (sleeping-time) in the LR rats than in the HR rats. The LR group was also shown to have a significantly lower density of [3H]-Flunitrazepam bound to the GABAA receptor in hippocampal membranes. Our data suggest that inter-individual differences in rearing are related, at least in part, to the GABA inhibitory neurotransmission controlled by the benzodiazepine allosteric site in the GABAA receptor.
文摘Background The first year of attending university induces a stressful experience for many college students. The experience exposes these students to challenging circumstances and raises expectations, which consequently increases the risk of psychiatric disorders and may exacerbate pre-existing problems. This study was designed to explore the risk factors of psychological symptoms among freshmen in China. Methods A three-year follow-up study was designed in a sample of Chinese college freshmen. To set up the baseline interviews, subjects from 25 high schools in Beijing were interviewed during the first year in high school. Three years later, we followed up with the 1547 students from 15 of the previously-selected 25 high schools after they had entered universities. Association between potential risk factors and the occurrence of psychological symptoms measured by the Symptoms Check List-90 was evaluated in unconditional logistic regression models with Wald test. Results Among the 1547 interviewed college freshmen in the study, 120 students （7.8%） manifested at least one psychological symptom. Personality dysfunction （OR=3.655, 95% CI 1.967-6.793）, parental rejection （OR=2.619, 95% CI 1.544-4.442）, age 〉 20 （OR=2.578, 95% CI 1.227-5.418）, disfavored university （OR=2.054, 95% CI 1.376-3.066）, non- first-choice academic major （OR=1.887, 95% CI 1.255-2.837） and no orientation （OR=1.739, 95% CI 1.025-2.951） were determined to be the risk factors of psychological symptoms among the college freshmen in China. Conclusions Psychological symptoms of college freshmen are associated with personality traits, parental rearing behavior and study environment. Therefore, it is important to pay attention to changes in mental health as students enter or decide on colleges and increase education geared towards mental health issues for students in high school and universities in China.
