Репозиторий Университета

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. Calcium ions (Ca2+) influx to mitochondrial matrix is crucial for the life of a cell. Mitochondrial calcium uniporter (mtCU) is a protein complex which consists of the pore-forming subunit (MCU) and several regulatory subunits. MtCU is the main contributor to inward Ca2+ currents through the inner mitochondrial membrane. Extensive investigations of mtCU involvement into normal and pathological molecular pathways started from the moment of discovery of its molecular components. A crucial role of mtCU in the control of these pathways is now recognized in both health and disease. In particular, impairments of mtCU function have been demonstrated for cardiovascular and skeletal muscle-associated pathologies. This review summarizes the current state of knowledge on mtCU structure, regulation, and function in different types of muscle tissues in health and disease.

© 2018 Scandinavian Physiological Society. Published by John Wiley  &  Sons Ltd Aim: During early post-natal development, arterial contraction depends less on Ca2+-signalling pathways but more on changes in Ca2+-sensitivity compared to adult animals. Whether this difference is related to Rho-kinase, one of the major players affecting Ca2+-sensitivity, is unknown for intact vessels. Thus, we tested the hypothesis that Rho-kinase critically contributes to the higher Ca2+-sensitivity of contraction in intact arteries of 1-week-old rats. Methods: We studied 1-week-old, 4- to 5-week-old and 10- to 12-week-old rats performing isometric myography, Ca2+-fluorimetry and Western blotting using intact saphenous arteries and arterial pressure measurements under urethane anaesthesia. Results: In 10- to 12-week-old rats, methoxamine (MX) produced vasoconstriction associated with an increase in [Ca2+]i and Ca2+-sensitivity. In contrast, in 1-week-old rats these contractions were accompanied only by an increase in Ca2+-sensitivity. All MX-induced effects were reduced by the Rho-kinase inhibitor Y-27632; this reduction was complete only in 1-week-old rats. The Rho-kinase specific site Thr855 on MYPT1 was increasingly phosphorylated by MX in vessels of 1-week-old, but not 10- to 12-week-old rats; this effect was also inhibited completely by Y-27632. The Rho-kinase inhibitor fasudil in a dose not affecting the pressor response to MX in 4- to 5-week-old rats reduced it considerably in 1-week-old rats. Conclusion: Our results suggest that the higher Ca2+-sensitivity of arterial contraction in 1-week-old compared to 10- to 12-week-old rats is due to a greater Rho-kinase activity. Constitutively active Rho-kinase contributes to MX-induced contraction in 10- to 12-week-old rats. In 1-week-old rats, additional Rho-kinase activation is involved. This remodelling of the Rho-kinase pathway is associated with its increased contribution to adrenergic arterial pressure responses.