T-tubule localization of the inward-rectifier K+ channel in mouse ventricular myocytes: a role in K+ accumulation

The properties of the slow inward ‘tail currents’ (Itail) that followed depolarizing steps in voltage-clamped, isolated mouse ventricular myocytes were examined. Depolarizing steps that produced large outward K+ currents in these myocytes were followed by a slowly decaying inward Itail on repolarization to the holding potential. These currents were produced only by depolarizations: inwardly rectifying K+ currents, IK1, produced by steps to potentials negative to the holding potential, were not followed by Itail.For depolarizations of equal duration, the magnitude of Itail increased as the magnitude of outward current at the end of the depolarizing step increased. The apparent reversal potential of Itail was dependent upon the duration of the depolarizing step, and the reversal potential shifted to more depolarized potentials as the duration of the depolarization was increased.Removal of external Na+ and Ca2+ had no significant effect on the magnitude or time course of Itail. BaCl2 (0.25 mm), which had no effect on the magnitude of outward currents, abolished Itail and IK1 simultaneously.Accordingly, Itail in mouse ventricular myocytes probably results from K+ accumulation in a restricted extracellular space such as the transverse tubule system (t-tubules). The efflux of K+ into the t-tubules during outward currents produced by depolarization shifts the K+ Nernst potential (EK) from its ‘resting’ value (close to −80 mV) to more depolarized potentials. This suggests that Itail is produced by IK1 in the t-tubules and is inward because of the transiently elevated K+ concentration and depolarized value of EK in the t-tubules.Additional evidence for the localization of IK1 channels in the t-tubules was provided by confocal microscopy using a specific antibody against Kir2.1 in mouse ventricular myocytes

When pictures take away from the message: An examination of young adults’ attention to texting and driving advertisements.

This study examined eye-movement patterns of young adults, while they were viewing texting and driving prevention advertisements, to determine which format attracts the most attention. As young adults are the most at risk for this public health issue, understanding which format is most successful at maintaining young adults’ attention is especially important. Participants viewed nondriving, general distracted driving, and texting and driving advertisements. Each of these advertisement types were edited to contain text-only, image-only, and text and image content. Participants were told that they had unlimited time to view each advertisement, while their eye-movements were recorded throughout. Participants spent more time viewing the texting and driving advertisements than other types when they comprised text only. When examining differences in attention to the text and image portions of the advertisements, participants spent more time viewing the images than the text for the nondriving and general distracted driving advertisements. However, for texting and driving-specific advertisements the text-only format resulted in the most attention toward the advertisements. These results indicate that in attracting young adults’ attention to texting and driving public health advertisements, the most successful format would be text-based