Nicotinamide-rich diet improves physical endurance by up-regulating SUR2A in the heart

作者：Sukhodub Andriy; Sudhir Rajni; Du Qingyou; Jovanovic Sofija; Reyes Santiago; Jovanovic Aleksandar^*

来源：Journal of Cellular and Molecular Medicine, 2011, 15(8): 1703-1712.

DOI：10.1111/j.1582-4934.2010.01156.x

• nicotinamide
• SUR2A
• endurance
• KATP channels

SUR2A is an ATP-binding protein that serves as a regulatory subunit of cardioprotective ATP-sensitive K(+) (KATP) channels. Based on signalling pathway regulating SUR2A expression and SUR2A role in regulating numbers of fully assembled KATP channels, we have suggested that nicotinamide-rich diet could improve physical endurance by stimulating SUR2A expression. We have found that mice on nicotinamide-rich diet significantly improved physical endurance, which was associated with significant increase in expression of SUR2A. Transgenic mice with solely overexpressed SUR2A on control diet had increased physical endurance in a similar manner as the wild-type mice on nicotinamide-rich diet. The experiments focused on action membrane potential and intracellular Ca(2+) concentration have demonstrated that increased SUR2A expression was associated with the activation of sarcolemmal KATP channels and steady Ca(2+) levels in cardiomyocytes in response to beta-adrenergic stimulation. In contrast, the same challenge in the wild-type was characterized by a lack of the channel activation and rise in intracellular Ca(2+). Nicotinamide-rich diet was ineffective to increase physical endurance in mice lacking KATP channels. This study has shown that nicotinamide-rich diet improves physical endurance by increasing expression of SUR2A and that this is a sole mechanism of the nicotinamide-rich diet effect. The obtained results suggest that oral nicotinamide is a regulator of SUR2A expression and has a potential as a drug that can improve physical endurance in conditions where this effect would be desirable.

• 出版日期2011-8