Intracelluar signal transduction of relaxin : comparative study with beta-adrenergic action

目的在于松弛素作用与cAMP和cGMP介导的作用如何相似和不同。在注射雌二醇-苯甲酸酯后72小时，取去卵巢大鼠的子宫纵行肌层。在无镁的Krebs溶液中通过电刺激诱发相性收缩。当组织暴露于含有15 mM Mg的无Ca的40 mX K溶液时，[Mg]i从对照溶液中的380 μ M增加到420 μ M。假设当暴露于0.6mM Mn时，肌细胞负载有Mn。收缩反应松弛素，异丙肾上腺素，毛喉素和环核苷酸衍生物进行了比较之前和之后的细胞内负荷与镁或锰。Mu（c）的胞内Mg（B）升高对db cAMP和8-溴cGMP引起的收缩抑制的影响，与异丙肾上腺素、毛喉素和松弛素引起的收缩抑制相比。蛋白激酶A的激活被认为是松弛素和肾上腺素能β-作用的共同途径（Hsu和Sanborn，1986）。提出的问题是，松弛素和db cAMP如何以及为什么表现出异丙肾上腺素和毛喉素的影响下，细胞内负荷与锰不同。

It was aimed how the relaxin action resembles and differs from cAMP-and cGMP-mediated effects. The longitudinal myometrium was taken from ovariectomized rat 72h after the injection of estradiol-benzoate. Phasic contractions were evoked in Mg-free Krebs solution by electrical stimulation. The [Mg]i was increased from 380muM in the control solution to 420muM, when the tissue was exposed to Ca-free 40mX K solution containing 15mM Mg. It was assumed that muscle cells were loaded with Mn, when exposed to 0.6mM Mn. Contractile responses to relaxin, isoprenaline, forskolin and cyclic nucleotide derivatives were compared before and after the intracellular load with Mg or Mn. Results are summarized in the table shown below.Influence of the elevation of intracellular Mg(b) of Mu(c) on the contractile inhibition caused by db cAMP and 8-bromo cGMP in comparison with that by isoprenaline, forskolin and relaxin. Upward and downward arrows indicate augmentation and attenuation of the inhibitory effects, respectively.The activation of protein kinase A is thought to be a common pathway of relaxin and adrenergic beta-action (Hsu and Sanborn, 1986). The questions are raised, how and why relaxin and db cAMP behabed differently from isoprenaline and forskolin under the influence of intracellular load with Mn.