The mechanisms behind this differential response to hypoxia in ch

The mechanisms behind this differential response to hypoxia in chorionic plate arteries vs. veins require further experimentation (e.g., other agonists and levels of pretone; responses to hypoxia at different intraluminal flow rates; mechanism(s) of detection of hypoxic challenge; role of K+ channels in effect). To summarize, the effect of hypoxia on placental blood vessels is relatively poorly

studied. At the macro-level, increased vascular resistance can be elicited following hypoxic challenge; however, the physiological relevance of these observations remains open to question. At the individual vessel level, the effects of hypoxia are inconsistent and the mechanisms of detection/response remain unclear. In 2005, the International Union of Pharmacology published a number of reviews of K+ channel nomenclature and molecular relationships learn more that succinctly summarize our knowledge of this ion channel superfamily [19, 23, 38, 73]. K+ channel α-subunits form a diverse group, clearly demonstrated by the number of genes that encode for protein. This basic structural diversity is further complicated by post-translational assembly of α-subunits into heterotetramers which may be constructed of different channel isoforms;

each α-subunit may Atezolizumab mw be coupled to any one of a range of different accessory/associated proteins (e.g., β-subunits; sulphonylurea receptor). This ability to “blend” subunits together produces a diversity of K+ selective pores in cell membranes with subtly different properties. Given this diversity of structure, coupled with the ability of K+ channels to influence cell membrane potential, it is perhaps unsurprising that K+ channels appear central to the function of so many cells. A wide variety of K+ channels have been demonstrated to be functionally expressed Adenylyl cyclase in endothelial and smooth muscle cells derived from systemic [29] or pulmonary vessels [2, 22, 49]. Indeed flux of K+ from endothelial cells

has been suggested to play a key role in the EDHF response of many systemic arteries [15]. Of special interest to the placental vascular physiologist are data from pulmonary vascular studies which suggest that some K+ channels are oxygen sensitive or are indirectly sensitive to oxygenation levels via the effects that ROS have on channel kinetics [2, 44]. The general lack of data focusing on K+ channel expression (e.g., vascular vs. trophoblast; endothelium vs. smooth muscle; large vs. small caliber vessels) and function (e.g., in the control of vascular tone) within the placenta is therefore unexpected. Guiet-Bara et al. [20, 21] isolated smooth muscle and endothelial cells from placental allantochorial blood vessels. The authors noted that, using specific K+ channel blockers in smooth muscle cells preparations, KV, KCa, and KATP channels regulated cell membrane potential.

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