BACKGROUND： It has been demonstrated that the septal nucleus is involved in the pathogenesis of schizophrenia. Based on autopsies of schizophrenia patients, studies have shown a reduced number of septal nucleus neuro...BACKGROUND： It has been demonstrated that the septal nucleus is involved in the pathogenesis of schizophrenia. Based on autopsies of schizophrenia patients, studies have shown a reduced number of septal nucleus neurons and glia. In addition, experimental rat models of schizophrenia have shown increased dopamine receptor D2 binding sites in the basal ganglia, septal nuclei, and substantia nigra. Previous studies have demonstrated that the septal nucleus modulates dopamine metabolic disorder and dopamine D2 receptor balance. OBJECTIVE： Dopamine D2 receptor expression in a rat model of schizophrenia, combined with antipsychotic drugs, was analyzed in the prefrontal lobe, striatum, and brainstem. In situ hybridization was used to observe the effects of stereotactic septal nucleus lesions on dopamine D2 receptor expression in the brains of methylamphetamine-treated rats. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed in the Laboratory of General Institute of Psychosurgery, Third Hospital of Chinese PLA from November 2005 to June 2006. MATERIALS： A total of 120 healthy, adult Sprague Dawley rats, weighing approximately 200 g, were included. Methylamphetamine （Sigma, USA） and an in situ hybridization detection kit for dopamine D2 receptor （Boster, China） were also used for this study. METHODS： All rats were randomly allocated to the following 4 groups, with 30 rats in each group： normal control, simple administration, septal nucleus lesion, and sham-operated groups. In the normal control group, rats were not administered or lesioned. In the remaining 3 groups, rats were intraperitoneally administered 10 mg/kg methylamphetamine, once per day, for 15 successive days to establish a schizophrenia model. Following successful model establishment, rats from the septal nucleus lesion group were subjected to stereotactic septal nucleus lesions. The cranial bone was exposed in rats from the sham-operated group, and the septal nucleus was not lesioned. MAIN OUTCOME MEASURES： At 7 days post-surgery, dopamine D2 receptor expression in the prefrontal lobe, striatum, and brainstem were detected by in situ hybridization. RESULTS： Dopamine D2 receptor expression in the rat prefrontal lobe, striatum, and brainstem was significantly higher in the simple administration group and sham-operated group, compared with the normal control group （P 〈 0.01）. In the septal nucleus lesion group, dopamine D2 receptor expression was significantly less than the simple administration and sham-operated groups, （P 〈 0.01）. There was no significant difference in dopamine D2 receptor expression between the simple administration and sham-operated groups （P 〉 0.05）. CONCLUSION： Septal nucleus lesions reduce dopamine D2 receptor expression in the prefrontal lobe, striatum, and brainstem in a rat model of schizophrenia, indicating that the septal nucleus modulates dopamine D2 receptor expression.展开更多
Background: Mechanisms underlying overeating-induced obesity in post-menopausal woman include functional lack of 17β-estradiol dysregulating dopamine D2 receptors, thereby inducing food addiction, glucose craving or ...Background: Mechanisms underlying overeating-induced obesity in post-menopausal woman include functional lack of 17β-estradiol dysregulating dopamine D2 receptors, thereby inducing food addiction, glucose craving or alcohol dependence through reward circuitry. This study aimed at further understanding 17β-estradiol and dopamine D2 receptors interferences in the etiology of woman obesity. Method: Seventy-two Wistar female rats weighing 200 - 205 g, individually-housed, were divided into non-ovariectomized control (C = 6 groups) and ovariectomized rats (OVX = 6 groups) which were concurrently subjected to the following treatments: Non-drug-treated (DMSO vehicle), 17β-estradiol (E2, 5 μg/kg, s.c.), sulpiride (SUL, 20 mg/kg, i.p.), bromocriptine (BR, 0.1 mg/kg, i.p.), E2 + SUL or E2 + BR, designating the 6 constitutive groups of either control or ovariectomy. Within each experimental group, consumption of different solutions (10% alcohol, 10% sucrose and water) as well as food intake and body weight were daily measured, for 10 consecutive days. Results: This study indicated that D2S was a specific inducer of alcohol and food intakes, but reduced sugar consumption. In addition, 17β- estradiol regulated the body weight set point, modulating D2S functions towards increased food intake at lower weights and decreased food intake at higher weights. D2S met the slow genomic actions induced by 17β-estradiol. Conversely, D2L inhibited alcohol and food intakes, but induced specifically sugar consumption, thereby regulating blood glucose levels and promoting energy expenditure in reducing body weight. Indeed, 17β-estradiol exerted a tonic inhibition on D2L which was released by OVX, exacerbating sugar intake and increasing body weight. D2L mediated the rapid metabolic effects of 17β-estradiol. Conclusion: Our results supported physiological data reporting that activation of the mostly expressed presynaptically D2S-class autoreceptors decreased dopamine release stimulating food intake, whereas activation of the predominantly postsynaptic isoform D2L receptors increased dopamine activity inhibiting food intake. Our studies indicated that 17β-estradiol acted on the two types of D2 receptors showing opposite functions to equilibrate energy intake vs. expenditure for weight set point regulation. Our data also supported biochemical findings reporting that 17β-estradiol induced D2 genes transcriptional regulation, thereby involving both types of D2 receptors in the etiology of obesity. The combined dysregulated effects of D2L and D2S receptors, as 17β-estradiol was lacking, would be causal factors underlying the etiology of obesity.展开更多
Behavioral and molecular characterization of cell-type specific populations governing fear learning and behavior is a promising avenue for the rational identification of potential therapeutics for fear-related disorde...Behavioral and molecular characterization of cell-type specific populations governing fear learning and behavior is a promising avenue for the rational identification of potential therapeutics for fear-related disorders.Identification of cell-type specific changes in neuronal translation following fear learning allows for targeted pharmacological intervention during fear extinction learning,mirroring possible treatment strategies in humans.Here we identify the central amygdala(Ce A)Drd2-expressing population as a fear-supporting population that is molecularly distinct from other,previously identified fear-supporting CeA populations.Sequencing of actively translating transcripts of Drd2 neurons identifies m RNAs that are differentially regulated following fear learning including Npy5r,Rxrg,Sst5r,Fgf3,Erb B4,Fkbp14,Dlk1,Ssh3 and Adora2a.Direct pharmacological manipulation of NPY5R,RXR,and ADORA2A confirms their importance in fear behavior and validates the present approach of identifying pharmacological targets for the modulation of emotional learning.展开更多
OBJECTIVE Cognitive inflexibility plays a critical role in the compulsive drug taking,a central characteristic of drug addictions,yet its underlying neurochemical mechanisms are not well understood.The present study e...OBJECTIVE Cognitive inflexibility plays a critical role in the compulsive drug taking,a central characteristic of drug addictions,yet its underlying neurochemical mechanisms are not well understood.The present study examined the impact of morphine withdrawal on reversal learning.METHODS Reversal learning was tested in a four-choices digging task.Some brain tissues were harvested 2 h after the behavioral experiment for the further measurement.RESULTS We found that after long-term abstinence for a month from chronic morphine exposure,mice exhibited a profound reversal learning deficit.We further found that dopamine D2 receptor(D2R)system in the frontal-striatal circuit is significantly down-regulated,at both receptor and downstream signals levels.Subsequent pharmacological experiments demonstrated that aripiprazole,a D2R partial agonist,prevented the D2R downregulation and rescued the reversal learning deficit.CONCLUSION Together,our findings provide valuable insights into the causal relationship between D2R system in the frontal-striatal circuit and the cognitive inflexibility caused by abused drugs and offer a promising possibility of an effective therapeutic intervention for drug addictions.展开更多
文摘BACKGROUND： It has been demonstrated that the septal nucleus is involved in the pathogenesis of schizophrenia. Based on autopsies of schizophrenia patients, studies have shown a reduced number of septal nucleus neurons and glia. In addition, experimental rat models of schizophrenia have shown increased dopamine receptor D2 binding sites in the basal ganglia, septal nuclei, and substantia nigra. Previous studies have demonstrated that the septal nucleus modulates dopamine metabolic disorder and dopamine D2 receptor balance. OBJECTIVE： Dopamine D2 receptor expression in a rat model of schizophrenia, combined with antipsychotic drugs, was analyzed in the prefrontal lobe, striatum, and brainstem. In situ hybridization was used to observe the effects of stereotactic septal nucleus lesions on dopamine D2 receptor expression in the brains of methylamphetamine-treated rats. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed in the Laboratory of General Institute of Psychosurgery, Third Hospital of Chinese PLA from November 2005 to June 2006. MATERIALS： A total of 120 healthy, adult Sprague Dawley rats, weighing approximately 200 g, were included. Methylamphetamine （Sigma, USA） and an in situ hybridization detection kit for dopamine D2 receptor （Boster, China） were also used for this study. METHODS： All rats were randomly allocated to the following 4 groups, with 30 rats in each group： normal control, simple administration, septal nucleus lesion, and sham-operated groups. In the normal control group, rats were not administered or lesioned. In the remaining 3 groups, rats were intraperitoneally administered 10 mg/kg methylamphetamine, once per day, for 15 successive days to establish a schizophrenia model. Following successful model establishment, rats from the septal nucleus lesion group were subjected to stereotactic septal nucleus lesions. The cranial bone was exposed in rats from the sham-operated group, and the septal nucleus was not lesioned. MAIN OUTCOME MEASURES： At 7 days post-surgery, dopamine D2 receptor expression in the prefrontal lobe, striatum, and brainstem were detected by in situ hybridization. RESULTS： Dopamine D2 receptor expression in the rat prefrontal lobe, striatum, and brainstem was significantly higher in the simple administration group and sham-operated group, compared with the normal control group （P 〈 0.01）. In the septal nucleus lesion group, dopamine D2 receptor expression was significantly less than the simple administration and sham-operated groups, （P 〈 0.01）. There was no significant difference in dopamine D2 receptor expression between the simple administration and sham-operated groups （P 〉 0.05）. CONCLUSION： Septal nucleus lesions reduce dopamine D2 receptor expression in the prefrontal lobe, striatum, and brainstem in a rat model of schizophrenia, indicating that the septal nucleus modulates dopamine D2 receptor expression.
文摘Background: Mechanisms underlying overeating-induced obesity in post-menopausal woman include functional lack of 17β-estradiol dysregulating dopamine D2 receptors, thereby inducing food addiction, glucose craving or alcohol dependence through reward circuitry. This study aimed at further understanding 17β-estradiol and dopamine D2 receptors interferences in the etiology of woman obesity. Method: Seventy-two Wistar female rats weighing 200 - 205 g, individually-housed, were divided into non-ovariectomized control (C = 6 groups) and ovariectomized rats (OVX = 6 groups) which were concurrently subjected to the following treatments: Non-drug-treated (DMSO vehicle), 17β-estradiol (E2, 5 μg/kg, s.c.), sulpiride (SUL, 20 mg/kg, i.p.), bromocriptine (BR, 0.1 mg/kg, i.p.), E2 + SUL or E2 + BR, designating the 6 constitutive groups of either control or ovariectomy. Within each experimental group, consumption of different solutions (10% alcohol, 10% sucrose and water) as well as food intake and body weight were daily measured, for 10 consecutive days. Results: This study indicated that D2S was a specific inducer of alcohol and food intakes, but reduced sugar consumption. In addition, 17β- estradiol regulated the body weight set point, modulating D2S functions towards increased food intake at lower weights and decreased food intake at higher weights. D2S met the slow genomic actions induced by 17β-estradiol. Conversely, D2L inhibited alcohol and food intakes, but induced specifically sugar consumption, thereby regulating blood glucose levels and promoting energy expenditure in reducing body weight. Indeed, 17β-estradiol exerted a tonic inhibition on D2L which was released by OVX, exacerbating sugar intake and increasing body weight. D2L mediated the rapid metabolic effects of 17β-estradiol. Conclusion: Our results supported physiological data reporting that activation of the mostly expressed presynaptically D2S-class autoreceptors decreased dopamine release stimulating food intake, whereas activation of the predominantly postsynaptic isoform D2L receptors increased dopamine activity inhibiting food intake. Our studies indicated that 17β-estradiol acted on the two types of D2 receptors showing opposite functions to equilibrate energy intake vs. expenditure for weight set point regulation. Our data also supported biochemical findings reporting that 17β-estradiol induced D2 genes transcriptional regulation, thereby involving both types of D2 receptors in the etiology of obesity. The combined dysregulated effects of D2L and D2S receptors, as 17β-estradiol was lacking, would be causal factors underlying the etiology of obesity.
文摘Behavioral and molecular characterization of cell-type specific populations governing fear learning and behavior is a promising avenue for the rational identification of potential therapeutics for fear-related disorders.Identification of cell-type specific changes in neuronal translation following fear learning allows for targeted pharmacological intervention during fear extinction learning,mirroring possible treatment strategies in humans.Here we identify the central amygdala(Ce A)Drd2-expressing population as a fear-supporting population that is molecularly distinct from other,previously identified fear-supporting CeA populations.Sequencing of actively translating transcripts of Drd2 neurons identifies m RNAs that are differentially regulated following fear learning including Npy5r,Rxrg,Sst5r,Fgf3,Erb B4,Fkbp14,Dlk1,Ssh3 and Adora2a.Direct pharmacological manipulation of NPY5R,RXR,and ADORA2A confirms their importance in fear behavior and validates the present approach of identifying pharmacological targets for the modulation of emotional learning.
文摘OBJECTIVE Cognitive inflexibility plays a critical role in the compulsive drug taking,a central characteristic of drug addictions,yet its underlying neurochemical mechanisms are not well understood.The present study examined the impact of morphine withdrawal on reversal learning.METHODS Reversal learning was tested in a four-choices digging task.Some brain tissues were harvested 2 h after the behavioral experiment for the further measurement.RESULTS We found that after long-term abstinence for a month from chronic morphine exposure,mice exhibited a profound reversal learning deficit.We further found that dopamine D2 receptor(D2R)system in the frontal-striatal circuit is significantly down-regulated,at both receptor and downstream signals levels.Subsequent pharmacological experiments demonstrated that aripiprazole,a D2R partial agonist,prevented the D2R downregulation and rescued the reversal learning deficit.CONCLUSION Together,our findings provide valuable insights into the causal relationship between D2R system in the frontal-striatal circuit and the cognitive inflexibility caused by abused drugs and offer a promising possibility of an effective therapeutic intervention for drug addictions.
