In Figure 1, which treatment has the highest peak tension overall? Is there evid
ID: 95459 • Letter: I
Question
In Figure 1, which treatment has the highest peak tension overall? Is there evidence that yellowfin tuna use SR Ca^2+ for muscle contractions? Explain. In the researcher's manuscript, they state: "In rainbow trout, maximal (1 mu mol l^-1) adrenergic stimulation overwhelms the relative importance of the intracellular (SR) Ca^2+ contribution to force production by dramatically increasing the peak force production of isolated heart muscle, even after it has been treated with ryanodine and irrespective of temperature. "Based on Figure 1, is there evidence that this trend is also true for yellowfin tuna? Explain.Explanation / Answer
1. In figure 1 control has highest peak tension overall because rynodine treatment increase absolute time require to reach to peak tension means decrease in peak tension. In this figure you can observed that control treatment has heighest peak tension in the absence of rynodine that dercrease the rate of contraction.
Yes, In the yellowfish tuna rynodine treatment decrease the forces at all temperature and frequency and leads to decrease in contraction. figure 1 suggest that time to peak force and and relaxation is inversaly proportional to temperature and frequency. SR Ca+2 utilitization is depend on temperature and frequency. Therefore decrease in temperature increase the probability to open SR calcium channel which contribute in contraction whereas in the presence of rynodine, peak force decrease with increase in temperature, SR calcium channel not open and relase of calcium disrupted leads to decrease in contraction of muscle. This indicates role of SR Ca+2 release in contraction of yellowfish tuna artrium.
2. According to figure 1, yellow fish tuna also follows the same pattern although at 150C the difference is not significant as compare to less adrenaline treatment. If you observe peak tension or peak force of both the treatment (rynodine + 1nmol AD and rynodine +1umol AD), it is heigher in the presence of maximal andrengenic (1 umol AD) stimulation frequency. Here, even in the presence of rynodine, adrenergic stimulation overcome the importance of intracellular calcium contribution thats why peak force increase. But still andregenic stimulation in the case of tuna fish has not significantly render the effect of rynodine treatment means not significantly overcome the imprtance of SR calcium concentration. In rainbow trout SR calcium contribution is overshadowed by sarcolemma calcium but it is not true in the case of yellowfish tuna.
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