BIOCHEMICAL CORRELATES OF 5-HT NEURONAL ACTIVITY

色氨酸羟基酶(TrpH)，合成过程中的限速酶 中枢神经系统中的5-羟色胺(5-HT)，将色氨酸转化为 5-羟色氨酸(5-HTP)在反应中也需要分子 氧气和还原的蝶呤辅因子。该项目重点关注以下因素 可能调节这种酶的活性，从而调节大脑中5-羟色胺的合成 在活体中，特别强调其改变的贡献 动力学行为可能会使。5-羟色胺神经元脉冲流增加 色氨酸在体内的羟基化及皮质的体外活性 TrpH与神经元放电对运动的影响分析 因此，该酶的性质是该项目的一个主要焦点。这些 研究将扩展到其他5-羟色胺投影区，特别是 有证据表明TrpH的调节特性可能是脊髓 不一样。阻断5-羟色胺脉冲血流对酶活性的影响 还将接受检查。我们将对它们的特性进行比较 体内激活的酶和体外激活的酶 磷酸化条件。还将探讨这样一种可能性 注射到其他物质的5-羟色胺神经元核(主要是 多肽)，可以在那里起到传递/调节作用 5-羟色胺神经元终末投射中的酶活性 对5-羟色胺神经元活动的影响。最后是酶活性的调节 在终末区域相对于细胞体以及在不同终末之间 将对字段进行比较。这项研究是由不同的证据推动的 多肽可以改变脑片或突触体内的酶活性，推测如下 直接受体介导的相互作用的结果，而不是通过效应 对5-羟色胺神经元放电频率的影响。将在体外测量酶的活性 在人工还原蝶呤辅因子的亚饱和浓度下， 6-甲基-5，6，7，8-四氢蝶呤或天然辅因子 四氢生物蝶呤和在体内，通过5-HTP在 脱羧酶抑制剂的存在，以确定 体外检测到的活性增加在体内表达。5-HTP 在每种情况下形成的将由高效液体隔离 高效液相色谱(HPLC法)和电化学检测法(EC)。 本研究有助于提高对5-羟色胺调节的认识 合成，一种中枢单胺递质，已知涉及 调节或调节各种各样的功能，包括情绪或 影响。

Tryptophan hydroxylase (TrpH), the rate limiting enzyme in the synthesis of 5-hydroxytryptamine (5-HT) in CNS, converts tryptophan to 5-hydroxytryptophan (5-HTP) in a reaction that also requires molecular oxygen and reduced pterin cofactor. The project focusses on factors that may regulate the activity of this enzyme and hence 5-HT synthesis in brain in vivo with particular emphasis on the contribution that changes in its kinetic behaviour may make. 5-HT neuronal impulse flow increases both the hydroxylation of tryptophan in vivo, and the in vitro activity of cortical TrpH and an analysis of the effects of neuronal firing on the kinetic properties of the enzyme is thus a major focus of the project. These studies will be extended to other 5-HT projection areas, particularly spinal cord where evidence exists that regulatory properties of TrpH may be different. The effects on enzyme activity of blockade of 5-HT impulse flow will also be examined. Comparisons will be made of the properties of enzyme activated in vivo with those of enzyme activated in vitro under phosphorylating conditions. The possibility will also be explored that administration into the 5-HT neuronal nuclei of other substances (largely peptides) that may serve a transmitter/modulator role there can influence enzyme activity in the terminal projections of 5-HT neurons e.g. through effects on 5-HT neuronal activity. Finally regulation of enzyme activity in terminal regions versus the cell body and between different terminal fields will be compared. This study is prompted by evidence that various peptides can alter enzyme activity in slices or synaptosomes presumably as a result of direct receptor mediated interactions rather than via effects on 5-HT neuronal firing rate. Enzyme activity will be measured in vitro under subsaturating concentrations of artificial reduced pterin cofactor, 6-methyl-5,6,7,8-tetrahydropterin (6MPH4) or the natural cofactor tetrahydrobiopterin and also in vivo, by the accumulation of 5-HTP in the presence of a decarboxylase inhibitor in order to determine whether increases in activity detected in vitro are expressed in vivo. The 5-HTP formed in each case will be isolated by high performance liquid chromatography (HPLC) and quantitated by electrochemical detection (EC). This study should enhance our understanding of the regulation of 5-HT synthesis, a central monoamine transmitter, which is known to be involved in modulating or regulating a wide variety of functions including mood or affect.