KChIP2 knockdown in isolated ventricular myocytes of the guinea pig prolongs the cardiac action potential.

<p><b>(A)</b> Immunoblot for KChIP2 of whole cell lysate isolated from ventricular cells treated for 24 hrs with adenovirus encoding either GFP (control) or an mRNA antisense sequence for KChIP2 (KChIP2 KD). Beta-actin was used as a loading control <b>(B)</b> Representative action potential tracings at 1000 ms cycle length from isolated ventricular cells following 24 hrs incubation with Ad.KChIP2-KD. <b>(C)</b> Summary data of APD₉₀ during 1000 ms and 400 ms cycle lengths. KChIP2 KD cells at 1000 ms (n = 16) show a significant prolongation of APD, compared to control cells (n = 14). KChIP2 KD at 400 ms (n = 11) was also significantly prolonged, compared to control cells (n = 9). <b>(D)</b> APD₅₀ following 1000 ms and 400 ms cycle lengths for the same treatment groups. Data presented as mean ± SEM; *<i>P</i> < 0.05; two-tailed Student’s <i>t</i>-test.