Key result
Dihydropyridine and ryanodine receptor densities significantly correlated with the expression of myosin heavy chain IIa (r=0.674 and r=0.645, respectively, p=0.01) in rat skeletal muscle.
Effect estimate: r = 0.674 (DHPR) and r = 0.645 (RyR)
p-value: p=0.01
No immediate clinical implications; leaves open fiber-type receptor roles in human muscle function.
In this study, the fiber type specificity of dihydropyridine receptors (DHPRs) and ryanodine receptors (RyRs) in different rat limb muscles was investigated. Western blot and histochemical analyses provided for the first time evidence that the expression of both receptors correlates to a specific myosin heavy chain (MHC) composition. We observed a significant (p=0.01) correlation between DHP as well as Ry receptor density and the expression of MHC IIa (correlation factor r=0.674 and r=0.645, respectively) in one slow-twitch, postural muscle (m. soleus), one mixed, fast-twitch muscle (m. gastrocnemius) and two fast-twitch muscles (m. rectus femoris, m. extensor digitorum longus). The highest DHP and Ry receptor density was found in the white part of m. rectus femoris (0.058+/-0.0060 and 0.057+/-0.0158 ODu, respectively). As expected, the highest relative percentage of MHC IIa was also found in the white part of m. rectus femoris (70.0+/-7.77%). Furthermore, histochemical experiments revealed that the IIA fibers stained most strongly for the fluorophore-conjugated receptor blockers. Our data clearly suggest that the expression of DHPRs and RyRs follows a fiber type-specific pattern, indicating an important role for these proteins in the maintenance of an effective Ca2+ cycle in the fast contracting fiber type IIA.
No takes yet. Share an insight, caveat, or question.
Anttila et al. (2007) studied Healthy (Skeletal Muscle) (n=6). Muscle fiber type (MHC IIa) vs. Other muscle fiber types was evaluated on Correlation between DHP/Ry receptor density and expression of MHC IIa (r = 0.674 (DHPR) and r = 0.645 (RyR), p=0.01). Dihydropyridine and ryanodine receptor densities significantly correlated with the expression of myosin heavy chain IIa (r=0.674 and r=0.645, respectively, p=0.01) in rat skeletal muscle.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: