Role of voltage‐gated potassium channels in the response to oxygen in chicken embryo ductus arteriosus

Abstract

Inhibition of voltage‐gated potassium (Kv) channels by O2 has been reported as a central mechanism involved in ductus arteriosus (DA) closure in mammals. Herein, we have investigated the role of Kv channels in the developmental and regional responses to O2 in chicken embryo DA. Experiments were performed in the pulmonary or aortic sides of the DA isolated from chicken embryos incubated for 15 or 20 days and in myocytes isolated from these tissues. Under control conditions, the amplitude of the potassium currents were similar in myocytes from the pulmonary or aortic sides of the 20‐day DA and around two fold higher than in 15‐day DA myocytes. The increase in O2 tension from 0 to 21% induced a partial (30±4%) and a total (96±4%) reduction of the current (measured at 0mV) in myocytes isolated from the pulmonary side of 15‐day and 20‐day DA, respectively. No effects were observed in myocytes isolated from the aortic side of the 20‐day DA. Addition of DPO‐1, a selective inhibitor of the Kv1 channels subfamily, markedly reduced the contraction induced by O2. Our results indicate that, like in mammals, inhibition of Kv channels (especially of the Kv1 subfamily) is involved in the contraction of chicken DA by oxygen. This inhibitory effect augments with maturation and is restricted to the pulmonary side of the DA.Supported by SAF2005‐03770 and Fundacion Mutua Madrileña