Hypergravity Increases and Simulated Microgravity Decreases the Ion Current through Mechanically Gated Channels...

Since hypergravity and simulated microgravity alter the morphological and physiological properties of the heart and the quantity of gene transcripts for mechanically gated channels (MGCs), it was hypothesized that cardiomyocyte sensitivity to stretching would be altered. Using the whole-cell patch-clamp technique during stretching of isolated cells, we have demonstrated that hypergravity in rats increases cardiomyocyte sensitivity to stretching, which manifests as a pronounced increase in the ion currents through MGCs in response to cell stretching. On the contrary, simulated microgravity substantially decreases cardiomyocyte sensitivity to stretching, which manifests as a significant reduction in stretch-induced currents through MGCs. Considering previously published data, we believe that these effects are based on the respective increase or decrease in MGC gene transcripts.