ИСТИНА

Potassium channels are key regulators of arterial smooth muscle membrane potential and vascular tone. The TASK-1 (TWIK-related acid-sensitive) potassium channel is a member of the two-pore domain potassium channel (K2P) family. TASK-1 channels have been shown to conduct background potassium currents in smooth muscle cells from pulmonary arteries. However, much less is known about their function in systemic arteries. Potassium channel function has been shown to be altered during postnatal ontogenesis. However, the role of K2P potassium channels to this process hasn’t been studied yet. Therefore, we tested the hypotheses that (1) TASK-1 CHANNELS CONTRIBUTE TO BASAL TONE AND CONTRACTION IN ARTERIES OF THE PERIPHERAL CIRCULATION and(2) THE IMPACT OF TASK-1 CHANNELS CHANGES DURING POSTNATAL DEVELOPMENT. We demonstrated that the (1) blockade of TASK-1 channels with AVE1231 caused the development of strong basal tone and an increase of the sensitivity to methoxamine in arteries of young, but not in adult rats, (2) the effects of AVE1231 in arteries from young rats were not reproduced by Kv1 channel blockade with DPO-1, (3) the effects of AVE1231 and DPO-1 in arteries of young rats were additive leading to the development of a stronger basal tone and considerably more increased contractile responses to methoxamine in comparison to AVE1231 alone and also (4) higher expression level of TASK-1 mRNA was observed in arteries from young rats. All this findings allow us to conclude that the anticontractile influence of AVE1231-sensitive TASK-1 channels is considerably higher in peripheral arteries of young compared to adult rats. This may be important for setting low peripheral resistance and arterial blood pressure during the perinatal age.