Changes of the potassium currents in rat aortic smooth muscle cells during postnatal development.
(2000) Pflügers Archiv - European journal of physiology — Vol. 441, n° 2-3, p. 388-397 (2000)
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- This study was designed to investigate the role and regulation of arterial K+ channels during postnatal development. Rat thoracic aortic segments were suspended for isometric tension and resting membrane potential (RMP) recording. Contraction in response to 4-aminopyridine (4-AP) was similar in 4-, 8- and 12-week-old rats but was higher in 1-day-old rats. Contraction in response to tetraethylammonium (TEA) increased after 4 weeks. TEA increased the contractions evoked by noradrenaline in the aorta from 8- and 12-week-old rats but not from 1-day- and 4-week-old rats. RMP did not change during development. Patch-clamp studies of freshly isolated smooth muscle cells from the same aortas bathed in Ca2+-free medium showed a voltage-dependent K+ current (IK) sensitive to 4-AP. This current remained stable at all ages whereas the density of the total IK, recorded in the presence of Ca2+, showed a twofold increase between 4 and 8 weeks. This current was highly sensitive to TEA and charybdotoxin. The binding site density of 125I-labelled charybdotoxin was threefold higher in the membranes of aortas from 12-week-old compared to 4-week-old rats. These results indicate that changes in K+ channel distribution occur in the rat aorta during postnatal development. These are related to an increase in the expression of charybdotoxin-sensitive Ca2+-activated K+ channels.
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Gomez, J. P., Ghisdal, P., & Morel, N. (2000). Changes of the potassium currents in rat aortic smooth muscle cells during postnatal development. Pflügers Archiv - European journal of physiology, 441(2-3), 388-397. https://doi.org/10.1007/s004240000442 (Original work published 2000)