Prior work has shown that systemic cocaine pretreatment augments cocaine conditioned place preference (CPP) in rats. In contrast, ghrelin receptor antagonism attenuates cocaine and amphetamine-induced CPP. In order to...Prior work has shown that systemic cocaine pretreatment augments cocaine conditioned place preference (CPP) in rats. In contrast, ghrelin receptor antagonism attenuates cocaine and amphetamine-induced CPP. In order to further investigate ghrelin’s role in dopamine-mediated reward, the present report examined whether pretreament with ghrelin, administered directly into the ventral tegmental area (VTA) of the midbrain, would potentiate the rewarding properties of cocaine as measured by CPP. Adult male Sprague-Dawley rats were given access to either side of the CPP chamber in order to determine initial side preferences. The rats were then restricted to either their non-preferred or preferred side over the course of conditioning which lasted for a total of 16 consecutive days. This was followed by a final test day to then reassess preference. On days where rats were confined to their non-preferred side, ghrelin (30-300 pmol) and cocaine (0.625-10 mg/kg IP) were administered immediately prior to the conditioning trial. On alternate days rats were treated with vehicle and placed into what was initially determined to be their preferred side. CPP was calculated as the difference in percentage of total time spent in the treatment-paired compartment during the post-conditioning session and the pre-conditioning session. Our results indicated that both cocaine and ghrelin elicited CPP and that ghrelin pretreatment potentiated the effect of cocaine on place preference. Overall, these findings provide additional support for the argument that ghrelin signaling within the VTA enhances the rewarding effects of psychostimulant compounds.展开更多
文摘Prior work has shown that systemic cocaine pretreatment augments cocaine conditioned place preference (CPP) in rats. In contrast, ghrelin receptor antagonism attenuates cocaine and amphetamine-induced CPP. In order to further investigate ghrelin’s role in dopamine-mediated reward, the present report examined whether pretreament with ghrelin, administered directly into the ventral tegmental area (VTA) of the midbrain, would potentiate the rewarding properties of cocaine as measured by CPP. Adult male Sprague-Dawley rats were given access to either side of the CPP chamber in order to determine initial side preferences. The rats were then restricted to either their non-preferred or preferred side over the course of conditioning which lasted for a total of 16 consecutive days. This was followed by a final test day to then reassess preference. On days where rats were confined to their non-preferred side, ghrelin (30-300 pmol) and cocaine (0.625-10 mg/kg IP) were administered immediately prior to the conditioning trial. On alternate days rats were treated with vehicle and placed into what was initially determined to be their preferred side. CPP was calculated as the difference in percentage of total time spent in the treatment-paired compartment during the post-conditioning session and the pre-conditioning session. Our results indicated that both cocaine and ghrelin elicited CPP and that ghrelin pretreatment potentiated the effect of cocaine on place preference. Overall, these findings provide additional support for the argument that ghrelin signaling within the VTA enhances the rewarding effects of psychostimulant compounds.
文摘目的观察针刺对海洛因复吸大鼠脑神经细胞凋亡的影响。方法采用剂量递增法复制海洛因成瘾大鼠模型,将40只Wistar大鼠平均分成正常组、模型组、针刺组、药物组,于实验第39天取4组大鼠海马、中脑腹侧被盖区(ventral tegmental area,VTA)脑组织,光镜下观察神经细胞坏死情况,采用脱氧核糖核苷酸末端转移酶介导的缺口末端标记法(terminal deoxynucleotidyl transferase mediated nick end labeling,TUNEL)检测脑神经细胞凋亡情况。结果光镜下可见模型组大鼠脑海马、VTA神经细胞丢失、变性较严重,核溶解消失,神经细胞变性坏死及间质水肿明显,并可见筛状软化灶。针刺组未见明显筛状软化灶,神经细胞变性坏死及间质水肿程度较模型组、药物组减轻。针刺组神经细胞间质水肿较轻,未见明显筛状软化灶,神经细胞水肿坏死变性较少量。与正常组比较,模型组大鼠脑海马、VTA中TUNEL染色阳性细胞数显著增多(P<0.01);与模型组、药物组比较,针刺组大鼠脑海马、VTA中TUNEL染色阳性细胞数显著减少(P<0.01)。结论海洛因成瘾可致大鼠脑神经细胞凋亡,针刺"百会"、"大椎"穴可抑制神经细胞凋亡。
