Store-Operated Calcium Entry Increases Nuclear Calcium in Adult Rat Atrial and Ventricular Cardiomyocytes.

Store-operated calcium entry (SOCE) in cardiomyocytes may be involved in cardiac remodeling, but the underlying mechanisms remain elusive. We hypothesized that SOCE may increase nuclear calcium, which alters gene expression via calcium/calmodulin-dependent enzyme signaling, and elucidated the underlying cellular mechanisms. An experimental protocol was established in isolated adult rat cardiomyocytes to elicit SOCE by re-addition of calcium following complete depletion of sarcoplasmic reticulum (SR) calcium and to quantify SOCE in relation to the electrically stimulated calcium transient (CaT) measured in the same cell before SR depletion. Using confocal imaging, calcium changes were recorded simultaneously in the cytosol and in the nucleus of the cell. In ventricular myocytes, SOCE was observed in the cytosol and nucleus amounting to ≈15% and ≈25% of the respective CaT. There was a linear correlation between the SOCE-mediated calcium increase in the cytosol and nucleus. Inhibitors of TRPC or Orai channels reduced SOCE by ≈33-67%, whereas detubulation did not. In atrial myocytes, SOCE with similar characteristics was observed in the cytosol and nucleus. However, the SOCE amplitudes in atrial myocytes were ≈two-fold larger than in ventricular myocytes, and this was associated with ≈1.4- to 3.6-fold larger expression of putative SOCE proteins (TRPC1, 3, 6, and STIM1) in atrial tissue. The results indicated that SOCE in atrial and ventricular myocytes is able to cause robust calcium increases in the nucleus and that both TRPC and Orai channels may contribute to SOCE in adult cardiomyocytes.

Effects of Chaenomeles maulei Fruit Juice on Reserpine-induced Behavioral Changes in Rats.

BACKGROUND: The fruit juice from. AIM: The aim of the current study was to investigate the effects of. MATERIALS AND METHODS: The experimental design included a total of 50 animals, divided in the following groups: control, R, R+CMFJ2.5, R+CMFJ5, and R+CMFJ10. All groups except the control received a single intraperitoneal injection of reserpine while the Control group was injected with the vehicle. CMFJ was applied through an orogastric cannula at 0, 19, and 23 hours after reserpine injection at doses of 2.5 ml/kg, 5 ml/kg, and 10 ml/kg to groups R+CMFJ2.5, R+CMFJ5, and R+CMFJ10, respectively. The groups control and R received distilled water (10 ml/kg) at the same time points. The open field test (OFT) and the forced swim test (FST) were carried out. In the OFT, crossings and rearings were recorded as a measure of locomotor activity. In the FST, the immobility time served as a measure of depressive-like behavior. RESULTS: In the OFT, the number of crossings of rats were significantly reduced (p<0.05) by reserpine. CMFJ antagonized the effects of reserpine on rat locomotor activity. In the FST, reserpine caused an insignificant reduction of the immobility time while CMFJ reversed this effect probably by increasing the locomotor activity. CONCLUSION: CMFJ reversed reserpine-induced hypokinesia in rats. This effect of CMFJ might be attributed to the polyphenols found in very high concentrations in the juice.