Vascular Effects of Perinatal Hypoxia in the Early Postnatal Period in Rats

The normal functioning of the vascular system in early ontogenesis can be altered by adverse exposures affecting the organism of the fetus/newborn during pregnancy, at birth, or in the postpartum period. However, the information on the “acute” (immediately after exposure) and “delayed” (after several days) effects of short-term (within several hours) perinatal normobaric hypoxia on the functioning of the peripheral vascular system of the systemic circulation in early ontogenesis in mammals is quite insufficient. The aim of this work was to study the “acute” and “delayed” single-session effects of a normobaric hypoxic exposure on the functioning of the systemic arteries in early postnatal ontogenesis. The contractile responses of the saphenous arteries in 10–14-day-old rats were studied in isometric mode. Acute normobaric hypoxia (8% O2) was simulated in 10-day-old rat pups for 2 h. The selected hypoxic regimen did not lead to changes in arterial contractile responses to the α1-adrenergic agonist methoxamine either immediately after exposure or several days later. Endothelium-dependent relaxation of the arteries to acetylcholine also did not differ between groups. Hypoxia did not change the contribution of anticontractile pathways associated with nitric oxide and Kv7 channels, as well as the procontractile role of Rho-kinase. Thus, short-term normobaric hypoxic exposure on postnatal day 10 leads to neither “acute” nor “delayed” changes in tone regulation of the peripheral arteries of the systemic circulation in the early postnatal period in rats.