Panatier Aude, Oliet Stephane H R
Inserm U378, Institut François Magendie, 33077 Bordeaux, France.
Neuron Glia Biol. 2006 Feb;2(1):51-8. doi: 10.1017/S1740925X06000019.
The supraoptic (SON) and paraventricular (PVN) magnocellular nuclei of the hypothalamus undergo reversible anatomical remodeling under conditions of intense secretion of neurohypophysial hormones, such as lactation and chronic dehydration. This morphological plasticity is characterized by a pronounced reduction in astrocytic coverage of neurons, which results in an increased number and extent of directly juxtaposed somatic and dendritic surfaces. As a consequence, astrocyte-mediated clearance of glutamate from the extracellular space is altered, which causes an increased concentration and range of action of the excitatory amino acid in the extracellular space. This leads to a reduction of synaptic efficacy at excitatory and inhibitory inputs through the activation of presynaptic metabotropic glutamate receptors. By contrast, the action of glio transmitters released from astrocytes and acting on adjacent magnocellular neurons is limited during such anatomical remodeling. This includes glia derived ATP mediating potentiation of glutamatergic transmission, a process compromised by the neuronal-glial reorganization.Together, these studies on hypothalamic magnocellular nuclei provide new insights on the contribution of glial cells on neuronal activity.
下丘脑的视上核（SON）和室旁核（PVN）的大细胞神经元在神经垂体激素大量分泌的情况下，如泌乳和慢性脱水，会经历可逆的解剖结构重塑。这种形态可塑性的特征是神经元的星形胶质细胞覆盖显著减少，这导致直接相邻的体细胞和树突表面数量增加和范围扩大。结果，星形胶质细胞介导的细胞外空间谷氨酸清除发生改变，导致细胞外空间兴奋性氨基酸的浓度和作用范围增加。这通过激活突触前代谢型谷氨酸受体导致兴奋性和抑制性输入处的突触效能降低。相比之下，在这种解剖结构重塑过程中，星形胶质细胞释放并作用于相邻大细胞神经元的神经胶质递质的作用受到限制。这包括胶质细胞衍生的ATP介导谷氨酸能传递的增强，这一过程因神经元 - 胶质细胞重组而受损。总之，这些关于下丘脑大细胞神经元的研究为胶质细胞对神经元活动的贡献提供了新的见解。
