Functional and Immunological Properties of Ryanodine Receptor in the Eel Skeletal Muscle

뱀장어 근육내 Ryanodine Receptor의 기능 및 면역학적 성질

To investigate the functional and immunological properties of the Ca-release channel in the sarcoplasmic reticulum(SR) of the eel skeletal muscle, $[^3H]ryanodine$ binding, SDS gel electrophoresis, $^{45}Ca\;release$ studies, and immunoblot assay were carried out in the SR of the eel skeletal muscle. Maximal binding sites(Bmax) and $K_D$ values of $[^3H]ryanodine$ for Ca-release channel of the SR of the eel skeletal muscle were $19.44{\pm}1.40\;pmole/mg$ protein and $15.55{\pm}1.69\;nM$, respectively. $[^3H]Ryanodine$ binding to RyR was increased by calcium and AMP. The SR of the eel skeletal muscle has two high molecular weight bands on the SDS PAGE. The mobility of upper band was more slower than the single band of the rabbit skeletal muscle, and that of the lower band was similar with the single band of canine cardiac muscle. Vesicular $^{45}Ca-release$ was activated by calcium. Ca-induced $^{45}Ca-release$ was significantly inhibited by $MgCl_2(2\;mM)$, ruthenium red$(10\;{/mu}M)$ or tetracaine(1 mM), but not by high concentration of calcium itself. AMP-induced $^{45}Ca-release$ was slightly occurred only in the absence of calcium, it was not inhibited by $MgCl_2$ or ruthenium red. Caffeine also increased $^{45}Ca-release$ from the SR vesicles, but it was not affected by $MgCl_2$ or ruthenium red. Polyclonal Ab against rat skeletal muscle RyR is reacted with that of rabbit, but not reacted with that of the eel skeletal muscle. These results suggested that ryanodine receptor of the SR of the eel skeletal muscle is showing some similar properties with that of mammalian skeletal muscle, but might be an another isotype channel having two bands which is less sensitive to AMP, not cross-reacted with antisera against rat RyR, and not inhibited by high concentration of calcium.