Frequency dependence of endocytosis in aortic baroreceptor neurons and role of group III mGluRs.
Frequency dependence of endocytosis in aortic baroreceptor neurons and role of group III mGluRs.
复制标题
主动脉压力感受器神经元内吞作用的频率依赖性和 III 组 mGluR 的作用。
DOI：
10.1152/ajpheart.2001.281.1.h387
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Hay,M
中科院分区：
文献类型：
--
作者：
Pamidimukkala,J;Hay,M
压力感受器传入和孤束核（NTS）之间的突触传递被认为表现出频率依赖性抑制。神经递质释放的减少和调节突触传递机制的改变被假设参与了在压力感受器传入神经元中观察到的活动依赖性抑制。本研究利用培养的主动脉压力感受器神经元和荧光染料FM 1 -43和FM 2 -10来表征内吞或囊泡回收过程及其对1）神经元激活频率、2）代谢型谷氨酸受体（mGluR）激活和3）细胞内外钙浓度的依赖性。在0.5（53 ± 4）、1.0（23 ± 1）和10.0 Hz（2.7 ± 0.2）的频率下施加10 s刺激后，以荧光单位测量的每个尖峰的内吞作用在较高频率下显著降低。用（RS）-环丙基-4-膦酰基苯基甘氨酸（CPPG）阻断III组mGluRs可促进所有频率的内吞作用，表明该受体亚型可能参与内吞作用的抑制。操纵胞吐后的细胞外和细胞内钙浓度对胞吞作用没有影响。这些结果表明，在体外观察到的内吞作用的频率依赖性抑郁症可能有助于压力感受器传入神经传递的频率依赖性抑郁症和第三组mGluRs抑制内吞作用。
Synaptic transmission between baroreceptor afferents and the nucleus tractus solitarius (NTS) is known to exhibit frequency-dependent depression. Reductions in neurotransmitter release and alterations in mechanisms regulating synaptic transmission are hypothesized to be involved in the activity-dependent depression observed in baroreceptor afferent neurons. The present study utilized cultured aortic baroreceptor neurons and the fluorescent dyes FM1-43 and FM2-10 to characterize the process of endocytosis or vesicle retrieval and its dependence on1) frequency of neuronal activation,2) metabotropic glutamate receptor (mGluR) activation, and3) calcium concentrations inside and outside the cell. Endocytosis per spike, measured in fluorescence units after a 10-s stimulus applied at frequencies of 0.5 (53 ± 4), 1.0 (23 ± 1), and 10.0 Hz (2.7 ± 0.2), was significantly depressed at higher frequencies. Blockade of group III mGluRs with (RS)-cyclopropyl-4-phosphonophenylglycine (CPPG) facilitated endocytosis at all frequencies, suggesting that this receptor subtype may be involved in the inhibition of endocytosis. Manipulating the extracellular and intracellular calcium concentrations subsequent to exocytosis had no effect on endocytosis. These results suggest that frequency-dependent depression of endocytosis observed in vitro could contribute to the frequency-dependent depression of baroreceptor afferent neurotransmission and that group III mGluRs inhibit endocytosis.