权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Neural mechanism underlying re-depression of crayfish tailflip habituation

小龙虾甩尾习惯再抑制的神经机制

基本信息

批准号：
15570060
负责人：
NAGAYAMA Toshiki
金额：
$ 2.3万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15570060/
关键词：
crayfish escape behavior learning memory CNS neurone octopamine serotonin 馴化再抑圧シナプス

项目摘要

Crayfish escape up and forwards by flipping its tail when intense stimulus is applied to their tailfan. This escape behavior is mediated by a pair of giant fiber, lateral giants (LGs). The LGs receive mechanosensory information via direct electrical and chemical synapses from the sensory afferents and disynaptically via ascending interneurones. Bath application of serotonin (5-HT) increased the EPSP amplitude of LGs in response to the sensory stimulation though their resting potential and membrane resistance remained consistent. To analyze the nature of 5-HT modulation, sensory responses of LG escape circuit neurones were analyzed under the mixture of membrane permeable cAMP analog, CPT-cAMP and cAMP phosphodiesterase inhibitor IBMX. As 5-HT superfusion, EPSP amplitude of LGs was increased by cAMP analog superfusion. The increase of response of LGs was reduced after about 30 min of washing with normal saline. The sensory responses of interneurones A and C also increased by cAMP analog. These results suggest 5-HT increases intrinsic level of cAMP in LG escape circuit.Bath application of biogic amines, serotonin (5-HT) or octopamine (OA) increased amplitude of LG EPSPs in response to sensory stimulation. To investigate the action of these biogic amines, LG activity was analyzed under the mixture of membrane permeable cAMP analogue (CPT-cAMP) and cAMP phosphodiesterase inhibitor (IBMX) or cGMP analogue (8-Br-cGMP) alone. The cAMP analogue increased LG activity while cGMP analogue had no effect. Adenylate cyclase inhibitor SQ22536 inhibited the effect of 5-HT but had no effect on OA. Iontophoretic injection of cAMP analogue, Sp-cAMP, directly into LG mimicked the modulatory effect of 5-HT. These results suggest 5-HT increases LG activity by promoting intrinsic level of cAMP in LG itself.

当强烈的刺激施加在它们的尾扇上时，小龙虾通过翻转尾巴向上和向前逃跑。这种逃逸行为是由一对巨纤维，侧巨人（LGs）介导的。LG通过直接的电和化学突触从感觉传入神经接收机械感觉信息，并通过上行中间神经元进行双突触。浴用5-羟色胺（5-HT）可增加LGS对感觉刺激的EPSP幅值，但其静息电位和膜电阻保持一致。为了分析5-HT调制的本质，在膜渗透性cAMP类似物、CPT-cAMP和cAMP磷酸二酯酶抑制剂IBMX的混合物下分析LG逃逸回路神经元的感觉反应。与5-HT灌流组相比，cAMP类似物灌流组的EPSP幅值明显增加。生理盐水冲洗30 min后，LGs的反应性增强减弱。cAMP类似物也能增加中间神经元A和C的感觉反应。结果提示，5-HT可增加LG逃避回路的内源性cAMP水平，而5-HT或章鱼胺（OA）可增加LG对感觉刺激的EPSP波幅。为了研究这些胺的作用，在膜渗透性cAMP类似物（CPT-cAMP）和cAMP磷酸二酯酶抑制剂（IBMX）的混合物或单独的cGMP类似物（8-Br-cGMP）下分析LG活性。cAMP类似物增加LG活性，而cGMP类似物没有影响。腺苷酸环化酶抑制剂SQ 22536可抑制5-HT的作用，但对OA无影响。将cAMP类似物Sp-cAMP直接注入LG，可模拟5-HT的调节作用。结果提示5-HT通过促进LG自身cAMP水平而增强LG活性。