Induction of tyrosine hydroxylase by nerve growth factor and by elevated K+ concentrations in cultures of dissociated sympathetic neurons
Induction of tyrosine hydroxylase by nerve growth factor and by elevated K+ concentrations in cultures of dissociated sympathetic neurons
复制标题
神经生长因子和解离交感神经元培养物中 K 浓度升高诱导酪氨酸羟化酶
作者：
F. Hefti;H. Gnahn;M. Schwab;H. Thoenen
新生大鼠颈上神经节解离交感神经元中，神经生长因子（NGF）和K′浓度升高可诱导酪氨酸羟化酶（TH）的产生。发现这两种诱导是由不同的机制介导的。交感神经元的培养需要10 rig/ml 2.5 S NGF的持续存在才能达到最大存活率。在以10 rig/ml培养5天的培养基中，将NGF浓度增加到100至1,000 rig/ml，再培养2至3天，可使TH特异性活性提高50%至100%。免疫滴定法证实TH活性升高是由于酶分子数量增加所致。ngf介导的TH诱导被环己亚胺阻断，而不是被a-amanitin阻断，这表明在转录后水平上有调控。二丁基CAMP和霍乱毒素均未能提高TH的活性，表明CAMP不作为第二信使。Ca ' +也是如此，因为ngf介导的TH诱导既不会被跨膜Ca2+通量抑制剂（D-600）也不会被canodulin抑制剂（三氟拉嗪）减少。在1000 ng NGF/ml培养基中培养1 - 3天，将培养物暴露在K浓度升高（55 mM）的培养基中，TH活性进一步增加约100%。在镀后第7天用K′浓度升高的培养基代替正常培养基时，刺激最大；此后14天后，将培养物切换到升高的K '浓度时，未观察到诱导作用。至于NGF， K+介导的TH增加是由于酶分子数量的增加（免疫滴定）。与ngf介导的诱导相反，K+介导的诱导似乎在转录水平上受到调节，因为它被a- amantin显著降低。通过对甲基三苯磷的摄取来评估，钾离子浓度增加对TH的诱导程度与膜电位的降低平行。降低培养基中Ca2 '浓度对TH诱导没有影响。然而，它被D-600、Mg2+和二苯基氢妥英等干扰跨膜Ca2+通量的物质所抑制。此外，三氟拉嗪和非洛地平选择性地干扰卡诺dulin介导的过程，可阻断TH的诱导。在高K+浓度下生长的细胞的电子显微镜下，含有钙沉淀的线粒体的发生率降低了40%，这表明K+诱导的去极化干扰了线粒体对Ca ' +的吸收。神经生长因子（NGF）是一种在周围神经系统交感神经元和感觉神经元的发育和功能维持中起核心作用的蛋白质。由德意志联邦共和国波恩的亚历山大·冯·洪堡基金会提供奖学金。目前地址：瑞士巴塞尔，山德士公司临床前研究中心，CH-4002。神经化学系，马克斯·普朗克精神病学研究所，D-8033 Martinsried，德国联邦共和国。NGF对交感神经元的影响是选择性诱导酪氨酸羟化酶（TH）和多巴胺，l&羟化酶（DBH），合成去甲肾上腺素所必需的酶（回顾，见Thoenen和Barde， 1980）。给新生或成年大鼠注射神经生长因子后，交感神经节和肾上腺髓质中这些酶的活性升高（Thoenen et al., 1971; Otten et al., 1977）。NGF选择性地诱导TH和DBH，而多巴脱羧酶（参与去甲肾上腺素合成的第三种酶）仅在NGF介导的超-程度上增加
Tyrosine hydroxylase (TH) is induced by nerve growth factor (NGF) as well as by elevated K’ concentrations in cultures of sympathetic neurons dissociated from superior cervical ganglia of newborn rats. The two inductions were found to be mediated by different mechanisms. Cultures of sympathetic neurons required the continuous presence of 10 rig/ml of 2.5 S NGF for maximal survival. Increasing the NGF concentration in cultures grown at 10 rig/ml for 5 days to 100 to 1,000 rig/ml for an additional 2 to 3 days resulted in an elevation of the specific TH activity by 50 to 100%. Immunotitration demonstrated that the elevated TH activity was due to an increased number of enzyme molecules. The fact that the NGF-mediated TH induction was blocked by cycloheximide but not by a-amanitin suggests a regulation at the post-transcriptional level. Both dibutyryl CAMP and cholera toxin failed to elevate the activity of TH, indicating that CAMP does not act as a second messenger. The same is true for Ca’+, since the NGF-mediated TH induction was neither reduced by an inhibitor of transmembrane Ca2+ flux (D-600) nor by an inhibitor of cahnodulin (trifluoperazine) . Exposing cultures grown at 1,000 ng of NGF/ml for 1 to 3 days to medium with elevated K’ concentrations (55 mM) resulted in a further increase of TH activity by about 100%. Stimulation was maximal when normal medium was replaced by medium with elevated K’ concentrations 7 days after plating; no inductioin was observed when cultures were switched to elevated K’ concentrations later than 14 days thereafter. As for NGF, the K+-mediated TH increase was due to an augmented number of enzyme molecules (immunotitration). In contrast to the NGF-mediated induction, the K+-mediated induction appeared to be regulated at the transcriptional level, since it was markedly reduced by a-amanitin. The extent of TH induction by increasing concentrations of K+ paralleled the reduction in membrane potential as assessed by the uptake of methyltriphenylphosphonium. Reduction of the Ca2’ concentrations in the medium had no influence on TH induction. However, it was inhibited by D-600, Mg2+, and diphenylhydantoin, substances interfering with transmembrane Ca2+ fluxes. Moreover, TH induction was blocked by trifluoperazine and felodipine, drugs interfering selectively with cahnodulin-mediated processes. In electron micrographs of cells grown at elevated K+ concentrations, the incidence of mitochondria containing calcium precipitates was reduced by 40%, suggesting that the K+-induced depolarization interfered with the mitochondrial sequestration of Ca’+. Nerve growth factor (NGF) is a protein which plays a central role in the development and maintenance of function of sympathetic and sensory neurons of the peripheral nervous system. One of the most characteristic ‘Supported by a fellowship from the Alexander von HumboldtStiftung, Bonn, Federal Republic of Germany. Present address: Preclinical Research, Sandoz AG, CH-4002, Basel, Switzerland. * To whom correspondence should be addressed at Department of Neurochemistry, Max Planck Institute for Psychiatry, D-8033 Martinsried, Federal Republic of Germany. 155 effects of NGF on sympathetic neurons is the selective induction of tyrosine hydroxylase (TH) and dopamine ,L&hydroxylase (DBH), enzymes necessary for the synthesis of norepinephrine (for review, see Thoenen and Barde, 1980). After the administration of NGF to newborn or adult rats, the activity of these enzymes is elevated in sympathetic ganglia and in the adrenal medulla (Thoenen et al., 1971; Otten et al., 1977). NGF selectively induces TH and DBH, whereas dopa decarboxylase, the third enzyme involved in norepinephrine synthesis, increases only to the extent of the NGF-mediated hyper-
神经生长因子对乙酰胆碱酯酶活性的调节。
DOI：
--
发表时间：
1981
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Greene,LA;Rukenstein,A
通讯作者：
Rukenstein,A
兔回肠中钙和钙调蛋白依赖性蛋白磷酸化。
影响因子：
3.5
作者：
Taylor,L;Guerina,VJ;Donowitz,M;Cohen,M;Sharp,GW
通讯作者：
Sharp,GW
高钾浓度对细胞培养中睫状神经节神经元生长和发育的影响。
影响因子：
2.7
作者：
Nishi,R;Berg,DK
通讯作者：
Berg,DK