Page 40 - F. Cell biology

[F. Cell biology-24]

Effect of Ifenprodil on Kv1.5 Channel Currents

Soobeen Hwang¹, Su-Hyun Jo¹

¹Physiology, School of Medicine, Kangwon National University, Chuncheon 200-701, Korea, ²BIT Medical

Convergence, Kangwon National University, Chuncheon 200-701, Korea

Ifenprodil(2-(4-benzyl-piperidino)-1-(4-hydroxyphenyl)-1-pro-panol) bind to but do not activate alpha-adrenergic
receptors thereby blocking the actions of endogenous or exogenous adrenergic agonists. Adrenergic alpha-

antagonists are used in the treatment of hypertension, vasospasm, peripheral vascular disease, shock, and

pheochromocytoma. Kv1.5 channels are expressed in the heart and pancreatic β-cells. The most studied is the
human Kv1.5 channel (hKv1.5), which is thought to underlie the ultra-rapidly activating delayed rectifier K+ current
Ikur found in human atrial myocytes. We examined the effect of ifenprodil on the human Kv1.5 channel using a

Xenopus oocyte expression system and a two-microelectrode voltage clamp technique. We examined the
reversibility of ifenprodil inhibition of Kv1.5 currents. Inhibition was reversible even after washing for 30 min, peak

currents reversed by 86%, steady-state reversed by 77%. And ifenprodil did not shift activation and inactivation
curve. These results suggested that ifenprodil inhibit Kv1.5 currents via a non-genomic mechanism, cannot cross

plasma membrane, the effect may be short lasting.