OBJECTIVE Cannabis can be rewarding or aversive.Cannabis reward is believed to be mediated by activation of cannabinoid CB1 receptors(CB1 Rs) on GABAergic neurons that disinhibit dopaminergic neurons in the ventral te...OBJECTIVE Cannabis can be rewarding or aversive.Cannabis reward is believed to be mediated by activation of cannabinoid CB1 receptors(CB1 Rs) on GABAergic neurons that disinhibit dopaminergic neurons in the ventral tegmental area(VTA).However,little is known about the mechanisms underlying cannabis aversion in rodents.Our study aimed at dig the mechanisms underlying cannabis aversion.METHODS We first created CB1-floxed mice and then generated conditional CB1-knockout mice(VgluT2-CB1-/-) in glutamatergic neurons that express vesicular glutamate transporter 2(VgluT2).We then used immunohistochemistry and RNAscope in situ hybridization assays to examine whether CB1 Rs are expressed in VTA GABAergic neurons and glutamatergic neurons.We also used Cre-dependent viral vector to express light-sensitive channelrhodopsin-2 into VTA glutamatergic neurons.Next,conditioned place preference and intracranial self-stimulation(ICSS) maintained by optical activation of VTA glutamatergic neurons were employed to evaluate the effects of Δ9-THC on brain reward function.RESULTS CB1 Rs are found not only on VTA GABAergic neurons,but also on VTA glutamatergic neurons that express vesicular glutamate transporter 2(VgluT2).Photoactivation of VTA glutamatergic neurons produced robust intracranial self-stimulation(ICSS) behavior,which was dose-dependently blocked by DA receptor antagonists,but enhanced by cocaine.In contrast,Δ9-tetrahydrocannabinol(Δ9-THC),the major psychoactive component of cannabis,produced dose-dependent conditioned place aversion and a reduction in the above optical ICSS in VgluT2-cre control mice,but not in VgluT2-CB1-/-mice.CONCLUSION Activation of CB1 Rs in VgluT2-expressing glutamate neurons produces aversive effects that might explain why cannabinoid is not rewarding in rodents and might also account for individual differences in the hedonic effects of cannabis in humans.展开更多
【目的】观察大麻素1型受体(CB1R)在C57B/L6小鼠神经元和胶质细胞的表达及其在实验性自身免疫性脑脊髓炎(EAE)小鼠中枢神经系统(CNS)和外周免疫器官的动态变化及其作用。【方法】取C57B/L6胎鼠的海马培养神经元及新生C57B/L6新生小鼠的...【目的】观察大麻素1型受体(CB1R)在C57B/L6小鼠神经元和胶质细胞的表达及其在实验性自身免疫性脑脊髓炎(EAE)小鼠中枢神经系统(CNS)和外周免疫器官的动态变化及其作用。【方法】取C57B/L6胎鼠的海马培养神经元及新生C57B/L6新生小鼠的皮层培养星形胶质细胞和小胶质细胞,观察CB1R蛋白的表达;观察正常对照、完全弗氏佐剂、EAE和特异性CB1R抑制剂(SR141716A,SR1)干预组小鼠的神经功能缺损症状和体质量变化;用real time PCR检测CB1R m RNA表达;Western blot和荧光免疫组织化学法检测CB1R蛋白表达;用ELISA法检测细胞因子IL-1β、IL-4、IL-10、IL-17、IL-6、TNF-α、IFN-γ浓度的变化。【结果】1C57B/L6小鼠神经元和小胶质细胞表达CB1R,星形胶质细胞不表达CB1R。2EAE小鼠神经元CB1R的表达显著低于CFA小鼠(P<0.01),小胶质细胞CB1R的表达显著高于CFA小鼠(P<0.01)。EAE小鼠脾脏中CB1R的表达与相同时点CFA小鼠无显著性差异(P>0.05)。3SR1干预促进EAE早发,上调EAE小鼠CNS和脾脏抗原特异性T细胞IL-17,TNF-α,IL-1β和IL-6的表达(P<0.05)。【结论】1神经元和小胶质细胞表达CB1R。2EAE小鼠脾脏中CB1R显著升高没有疾病特异性,可能与非特异性免疫激活有关。3中枢神经细胞上的CB1R可能兼有神经保护和免疫调节双重作用,参与EAE的发生和发展。展开更多
文摘OBJECTIVE Cannabis can be rewarding or aversive.Cannabis reward is believed to be mediated by activation of cannabinoid CB1 receptors(CB1 Rs) on GABAergic neurons that disinhibit dopaminergic neurons in the ventral tegmental area(VTA).However,little is known about the mechanisms underlying cannabis aversion in rodents.Our study aimed at dig the mechanisms underlying cannabis aversion.METHODS We first created CB1-floxed mice and then generated conditional CB1-knockout mice(VgluT2-CB1-/-) in glutamatergic neurons that express vesicular glutamate transporter 2(VgluT2).We then used immunohistochemistry and RNAscope in situ hybridization assays to examine whether CB1 Rs are expressed in VTA GABAergic neurons and glutamatergic neurons.We also used Cre-dependent viral vector to express light-sensitive channelrhodopsin-2 into VTA glutamatergic neurons.Next,conditioned place preference and intracranial self-stimulation(ICSS) maintained by optical activation of VTA glutamatergic neurons were employed to evaluate the effects of Δ9-THC on brain reward function.RESULTS CB1 Rs are found not only on VTA GABAergic neurons,but also on VTA glutamatergic neurons that express vesicular glutamate transporter 2(VgluT2).Photoactivation of VTA glutamatergic neurons produced robust intracranial self-stimulation(ICSS) behavior,which was dose-dependently blocked by DA receptor antagonists,but enhanced by cocaine.In contrast,Δ9-tetrahydrocannabinol(Δ9-THC),the major psychoactive component of cannabis,produced dose-dependent conditioned place aversion and a reduction in the above optical ICSS in VgluT2-cre control mice,but not in VgluT2-CB1-/-mice.CONCLUSION Activation of CB1 Rs in VgluT2-expressing glutamate neurons produces aversive effects that might explain why cannabinoid is not rewarding in rodents and might also account for individual differences in the hedonic effects of cannabis in humans.
文摘【目的】观察大麻素1型受体(CB1R)在C57B/L6小鼠神经元和胶质细胞的表达及其在实验性自身免疫性脑脊髓炎(EAE)小鼠中枢神经系统(CNS)和外周免疫器官的动态变化及其作用。【方法】取C57B/L6胎鼠的海马培养神经元及新生C57B/L6新生小鼠的皮层培养星形胶质细胞和小胶质细胞,观察CB1R蛋白的表达;观察正常对照、完全弗氏佐剂、EAE和特异性CB1R抑制剂(SR141716A,SR1)干预组小鼠的神经功能缺损症状和体质量变化;用real time PCR检测CB1R m RNA表达;Western blot和荧光免疫组织化学法检测CB1R蛋白表达;用ELISA法检测细胞因子IL-1β、IL-4、IL-10、IL-17、IL-6、TNF-α、IFN-γ浓度的变化。【结果】1C57B/L6小鼠神经元和小胶质细胞表达CB1R,星形胶质细胞不表达CB1R。2EAE小鼠神经元CB1R的表达显著低于CFA小鼠(P<0.01),小胶质细胞CB1R的表达显著高于CFA小鼠(P<0.01)。EAE小鼠脾脏中CB1R的表达与相同时点CFA小鼠无显著性差异(P>0.05)。3SR1干预促进EAE早发,上调EAE小鼠CNS和脾脏抗原特异性T细胞IL-17,TNF-α,IL-1β和IL-6的表达(P<0.05)。【结论】1神经元和小胶质细胞表达CB1R。2EAE小鼠脾脏中CB1R显著升高没有疾病特异性,可能与非特异性免疫激活有关。3中枢神经细胞上的CB1R可能兼有神经保护和免疫调节双重作用,参与EAE的发生和发展。
