AUTORADIOGRAPHIC AND ELECTROPHYSIOLOGICAL EVIDENCE FOR THE EXISTENCE OF NEUROTENSIN RECEPTORS ON CULTURED ASTROCYTES
AUTORADIOGRAPHIC AND ELECTROPHYSIOLOGICAL EVIDENCE FOR THE EXISTENCE OF NEUROTENSIN RECEPTORS ON CULTURED ASTROCYTES
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DOI：
10.1016/0306-4522(95)00005-4
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发表时间：
1995-06-01
期刊：
影响因子：
3.3
通讯作者：
HOSLI, L
中科院分区：
文献类型：
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作者：
HOSLI, E;STAUFFER, S;HOSLI, L
用放射自显影法研究了[H-3]神经降压素及其非肽受体拮抗剂[H-3]SR-48692在大鼠新皮层、纹状体、脑干和脊髓组织块培养中结合位点的细胞定位。在所有研究的中枢神经系统区域的大量星形胶质细胞上观察到肽及其拮抗剂的结合位点。用抗胶质细胞酸性蛋白的单克隆抗体对培养物同时染色表明，在培养物的生长区中的标记细胞是胶质细胞酸性蛋白阳性的，因此可以鉴定为星形胶质细胞。除了星形胶质细胞，许多神经元和生长的神经纤维标记的放射性配体。[H-3]神经降压素和[H-3]SR-48692（10（-8）M）与神经元和神经胶质细胞的结合被高浓度（10（-6）M）的未标记化合物显著降低或抑制，表明放射性配体的“特异性"结合。电生理学研究表明，在浴液中加入神经降压素会引起大多数受试星形胶质细胞的超极化。超极化的幅度与肽的浓度（10（-10）-10（-7）M）之间存在剂量-反应关系; 10（-10）M为阈值浓度。选择性非肽类神经降压素受体拮抗剂SR-48692可逆地阻断或显著降低了所有星形胶质细胞的超极化，证实了神经降压素作用的特异性，我们的电生理研究结果与放射自显影数据一起为星形胶质细胞上存在特异性和功能性神经降压素受体提供了强有力的证据。
By means of autoradiography we have studied the cellular localization of binding sites for [H-3]neurotensin and its nonpeptide receptor antagonist [H-3]SR-48692 in explant cultures of rat neocortex, striatum, brain stem and spinal cord. Binding sites for the peptide and its antagonist were observed on a great number of astrocytes in all CNS regions studied. Simultaneous staining of the cultures with a monoclonal antibody against glial fibrillary acidic protein has shown that the labelled cells in the outgrowth zone of the cultures were glial fibrillary acidic protein-positive and could therefore be identified as astrocytes. In addition to astrocytes, many neurons and outgrowing nerve fibres were labelled by the radioligands. Binding of [H-3]neurotensin and [H-3]SR-48692 (10(-8)M) to neurons and glial cells was markedly reduced or inhibited by the unlabelled compounds at high concentration (10(-6)M), suggesting ''specific'' binding of the radioligands. Electrophysiological studies have shown that addition of neurotensin to the bathing solution caused a hyperpolarization of the majority of astrocytes tested. There was a dose-response relationship between the magnitude of the hyperpolarization and the concentration of the peptide (10(-10)-10(-7)M); 10(-10)M being the threshold concentration. The specificity of the action of neurotensin was confirmed by the selective nonpeptide neurotensin receptor antagonist SR-48692 which reversibly blocked or markedly reduced the hyperpolarization by the peptide on all astrocytes tested.Our electrophysiological findings together with our autoradiographic data provide strong evidence for the presence of specific and functional neurotensin receptors on astrocytes.