PHARMACOLOGY OF RYANODINE AND SR CALCIUM RELEASE

实验的目标首先是确定体外效果 兰尼碱和一系列兰尼碱对钙的结构类似物 分离自 SR 膜的渗透性和钙结合特性 骨骼、心脏和血管平滑肌。 Second, we will determine 这些化合物作用的生理后果 表征它们对完整肌肉功能产生的变化 准备工作。 在初步研究中我们发现两种二萜 ryanodine 的酯类似物，指定为 A 和 B，每种仅导致其中一种 兰尼丁的作用。 因此，这些化合物可以选择性地增加 并降低 SR 膜的钙渗透性，并可能激活和 抑制钙释放通道。 1. 我们将从Ryania木材中提取并纯化以下化合物： 兰尼定、脱氢兰尼定和指定为 A、B、C1 的二萜酯， C2和D。此外，ryanodine将被化学修饰形成 9-表吡雅诺定、异去氢雅诺定、脱水雅诺定、氧化雅诺定、 ryanodol and pyrrole-2-carboxylic acid. 2. 在一系列体外研究中，我们将建立并比较 兰尼定及其类似物对被动和主动钙通量的影响 穿过从骨骼分离的 SR 膜并与钙结合， 心脏和平滑肌。 We will also determine the effects of these 化合物对钙的电导和活化特性的影响 发现膜组分掺入脂质双层的通道 be affected by the alkaloids. Ineffective compounds will be tested for 它们拮抗那些被发现起作用的化合物的作用的能力 one of the sites affected by ryanodine. The structure-activity information 从这些研究中获得的结果将用于确定结构 兰尼碱分子的特征对于每项活动都很重要。 3. 我们将确定每种化合物改变速率的能力 耗氧量、细胞质钙活性以及机械和 完整骨骼、心脏和平滑肌的电功能。 我们 将关联这些中获得的结构-活性关系 与上一步中确定的那些进行现场研究，以便 建立体外实验之间存在的因果关系 SR 钙运动的变化和完整肌肉的变化 function produced by these compounds.

The goals of the experiments first, to establish the in vitro effects of ryanodine and a series of structural analogs of ryanodine on the calcium permeability and calcium binding properties of SR membranes isolated from skeletal, cardiac and vascular smooth muscles. Second, we will determine the physiological consequences of the actions of these compounds by characterizing the changes they produce in the function of intact muscle preparations. In preliminary studies we have found that two diterpine ester analogs of ryanodine, designated A and B, each cause only one of the effects of ryanodine. Therefore, these compounds may selectively increase and decrease a SR membrane calcium permeability and perhaps activate and inhibit the calcium release channel. 1. We will extract and purify the following compounds from Ryania wood: Ryanodine, dehydroryanodine, and the diterpine esters designated A, B, C1, C2 and D. In addition, ryanodine will be chemically modified to form 9-epiryanodine, isodehydroryanodine, anhydroryanodine, oxoryanodine, ryanodol and pyrrole-2-carboxylic acid. 2. In a series of in vitro investigations we will establish and compare the effects of ryanodine and its analogs on passive and active calcium fluxes across, and calcium binding by, SR membranes isolated from skeletal, cardiac and smooth muscles. We will also determine the effects of these compounds on the conductance and activation characteristics of calcium channels incorporated into lipid bilayers from membrane fractions found to be affected by the alkaloids. Ineffective compounds will be tested for their ability to antagonize the actions of those compounds found to act at one of the sites affected by ryanodine. The structure-activity information obtained from these studies will be used to identify the structural features of the ryanodine molecule which are important for each activity. 3. We will determine the ability of each compound to alter the rate of oxygen consumption, cytoplasmic calcium activity and the mechanical and electrical functions of intact skeletal, cardiac and smooth muscles. We will correlate the structure-activity relationships obtained in these in situ studies with those determined in the preceding step in order to establish the cause and effect relationships existing between the in vitro changes in SR calcium movements and the alterations in intact muscle function produced by these compounds.