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Background: The effects of α-tocopherol on intracellular Ca2+ intensity in semen cryopreservation by regulate intracellular Ca2+ intensity have not been reported yet. Objective: The research was conducted to evaluate the effect of supplementation α-tocopherol into egg yolk skim milk extender on sperm quality and intracellular Ca2+ intensity. Methods: Semen samples were collected and supplemented with respectively 0mM (P0); 0.5mM (P1); 1mM (P2); 1.5mM (P3) and 2mM (P4) α-tocopherol in extender before cryopreservation processes. Post-thawing sperm was evaluated for motility, viability, and abnormality using Phase Contrast Microscope (200x) with eosin-nigrosine staining, and intracellular Ca2+ intensity of the best result dose was evaluated using Confocal Laser Scan Microscope (400x) with Fluo-3 Staining. Results: The results showed there was a significant difference (P≤0.05) in sperm motility and viability between P0; P1 with P2; P3; P4. The Motility and viability between groups P0; P1 and P3; P4 showed no significant difference (P≥0.05), while P2 with P3; P4 showed significant difference (P≤0.05). There was a significant difference (P≤0.05) in sperm abnormality of P0; P1 with P2; P3; P4. The abnormality between P0; P1 and P2; P3 showed no significant difference (P≥ 0.05), while P2; P3 showed a significant difference with P4 (P≤0.05). The best result in sperm quality was supplementation with 1.5mM α-tocopherol. Ca2+ intracellular intensity: 142.76 ± 21.8 au (P0) and 176.06 ± 61.43 au (P3). Conclusions: It was concluded that 1.5mM α-tocopherol is the best dose to improve sperm quality by regulating intracellular Ca2+ intensity on Simmental bull cattle.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a malignant arrhythmia syndrome linked to mutations in the cardiac ryanodine receptor (RyR2) and calsequestrin (CASQ2). RyR2 and CASQ2 are parts of the multimolecular Ca2+ release channel complex that is present on the sarcoplasmic reticulum (SR) to support myocyte Ca2+ cycling and contractile activity. Whereas RyR2 operates as a Ca2+ release channel, the SR Ca2+ binding protein CASQ2 plays a dual role by serving as a SR Ca2+ buffer and by regulating RyR2 function. Essential to stable Ca2+ cycling, SR luminal Ca2+-dependent control of RyR2 activity by CASQ2 contributes to RyR2 deactivation and to the development of a temporary refractory state that occurs after each Ca2+ release. Accumulating evidence suggests that the CPVT mutations act by reducing the extent and shortening the duration of Ca2+ signaling refractoriness, thereby promoting untimely SR Ca2+ release and arrhythmogenic delayed afterdepolarizations in cardiac myocytes. Similar mechanisms may apply to arrhythmias during various conditions, including heart failure and ischemic heart disease, associated with acquired defects in components of the Ca2+ release channel complex. [Copyright &y& Elsevier]