Key result
Horse heart tissue expresses ERG1, KCNQ1, and KCNE1 proteins that coassociate and mediate repolarizing currents, indicating a risk for acquired long QT syndrome in horses.
Repolarizing currents in horses are similar to those of other species, suggesting horses are at risk for acquired long QT syndrome and providing evidence for coassociation between ERG1 and KCNE1 in cardiac tissue.
May support caution with QT-prolonging drugs in horses; leaves open translation to veterinary practice.
In dogs and in humans, potassium channels formed by ether-a-go-go-related gene 1 protein ERG1 (KCNH2) and KCNQ1 alpha-subunits, in association with KCNE beta-subunits, play a role in normal repolarization and may contribute to abnormal repolarization associated with long QT syndrome (LQTS). The molecular basis of repolarization in horse heart is unknown, although horses exhibit common cardiac arrhythmias and may receive drugs that induce LQTS. In horse heart, we have used immunoblotting and immunostaining to demonstrate the expression of ERG1, KCNQ1, KCNE1, and KCNE3 proteins and RT-PCR to detect KCNE2 message. Peptide N-glycosidase F-sensitive forms of horse ERG1 (145 kDa) and KCNQ1 (75 kDa) were detected. Both ERG1 and KCNQ1 coimmunoprecipitated with KCNE1. Cardiac action potential duration was prolonged by antagonists of either ERG1 (MK-499, cisapride) or KCNQ1/KCNE1 (chromanol 293B). Patch-clamp analysis confirmed the presence of a slow delayed rectifier current. These data suggest that repolarizing currents in horses are similar to those of other species, and that horses are therefore at risk for acquired LQTS. The data also provide unique evidence for coassociation between ERG1 and KCNE1 in cardiac tissue.
No takes yet. Share an insight, caveat, or question.
Finley et al. (2002) studied Cardiac repolarization / Long QT syndrome. ERG1 and KCNQ1/KCNE1 antagonists (MK-499, cisapride, chromanol 293B) was evaluated on Cardiac action potential duration and presence of slow delayed rectifier current. Horse heart tissue expresses ERG1, KCNQ1, and KCNE1 proteins that coassociate and mediate repolarizing currents, indicating a risk for acquired long QT syndrome in horses.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: