KREBS CYCLE AND CYCLIC NUCLEOTIDE CONTROL

调查的目的是评估和确定 加速的环核苷酸代谢流， 细胞cGMP或cAMP水平的变化与 兴奋性细胞刺激。 这种环核苷酸参与的模型， 与它们通过细胞内的变化介导的影响相反， 浓度建议从调查的光转导和 从最近关于平滑肌收缩的研究中， 与细胞内Ca 2+释放有关的兴奋生化过程。 环核苷酸的这种参与将在以下方面进行评估： 平滑肌和骨骼肌的兴奋/收缩偶联， 腮腺和血小板中的兴奋/分泌偶联。 环核苷酸和5'-脱氧核糖核酸的检测技术 完整细胞中核苷酸代谢的掺入率 氧18从[氧18]水进入α-，β-和 鸟嘌呤和腺嘌呤核苷酸的γ-磷酰基将用于 评估环核苷酸代谢与细胞兴奋的关系 并获得有关信息：1）排他性的 磷酸二酯酶途径标记细胞腺嘌呤和鸟嘌呤 核苷酸α-磷酰基; 2）细胞代谢产物的鉴定 一种似乎来源于cAMP水解的途径，导致快速供氧 18用刺激收缩标记IMP; 3）细胞高能 磷酸盐代谢和Pi转运与兴奋性和 适应性细胞刺激; 4）细胞代谢的定义 受影响的环核苷酸和5'核苷酸的区室 兴奋性和适应性刺激; 5）强度关系， 对细胞cGMP和cAMP的兴奋性刺激的频率和持续时间 代谢通量;和6）兴奋诱导的加速的关系， 环核苷酸代谢通量与细胞内Ca 2+释放的关系。 这些相关研究将通过实验来补充，以获得 信息; 7）动力学和调节特性， 与细胞结构相关的磷酸二酯酶和核苷酸环化酶 肌肉中Ca 2+的吸收和释放能力;以及8）关系 环核苷酸水解对离体肌肉Ca ~（2+）释放的影响 三合会

The investigations are aimed at assessing and defining the significance of the accelerated cyclic nucleotide metabolic flux that occurs without changes in cell cGMP or cAMP levels in association with the action of excitatory cell stimuli. This model of cyclic nucleotide involvement which contrasts with their influence mediated through changes in their cellular concentration is suggested from investigations of phototransduction and from more recent studies on contraction in smooth muscle to represent a biochemical process in excitation related to intracellular Ca2+ release. This involvement of cyclic nucleotides will be assessed with regard to excitation/contraction coupling in smooth and skeletal muscle and excitation/secretion coupling in parotid gland and platelets. The newly devised technology of monitoring cyclic nucleotide and 5' nucleotide metabolism in intact cells by the rate of incorporation of oxygen 18 from [oxygen 18] water into the Alpha-, Beta- and Gamma-phosphoryls of guanine and adenine nucleotides will be employed to assess the relationship of cyclic nucleotide metabolism to cell excitation and obtain information regarding: 1) the exclusivity of the phophodiesterase pathway in labeling cellular adenine and guanine nucleotide Alpha-phosphoryls; 2) identification of the cellular metabolic pathway that appears to derive from cAMP hydrolysis leading to rapid oxygen 18 labeling of IMP with stimulated contraction; 3) cellular high energy phosphate metabolism and Pi transport associated with excitatory and adaptive cell stimulation; 4) definition of the cellular metabolic compartments of cyclic nucleotides and 5' nucleotides affected by excitatory and adaptive stimulation; 5) relationship of intensity, frequency and duration of excitatory stimulation to cellular cGMP and cAMP metabolic flux; and 6) relationship of excitation-induced acceleration of cyclic nucleotide metabolic flux to intracellular Ca2+ release. These correlative studies will be supplemented by experiments to obtain information regarding; 7) the kinetic and regulatory characteristics of phosphodiesterases and nucleotidyl cyclases associated with cell structures in muscle with Ca2+ uptake and release capability; and 8) the relationship of cyclic nucleotide hydrolysis to the release of Ca2+ from isolated muscle triads.