scholarly journals Calcium release by noradrenaline from central sarcoplasmic reticulum in rabbit main pulmonary artery smooth muscle.

1985 ◽  
Vol 366 (1) ◽  
pp. 153-175 ◽  
Author(s):  
D Kowarski ◽  
H Shuman ◽  
A P Somlyo ◽  
A V Somlyo
Keyword(s):  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Pulmonary Artery ◽  
Calcium Release ◽  
Main Pulmonary Artery ◽  
Pulmonary Artery Smooth Muscle

scholarly journals Type-3 Ryanodine Receptors Mediate Hypoxia-, but Not Neurotransmitter-induced Calcium Release and Contraction in Pulmonary Artery Smooth Muscle Cells

2005 ◽  
Vol 125 (4) ◽  
pp. 427-440 ◽  
Author(s):  
Yun-Min Zheng ◽  
Qing-Song Wang ◽  
Rakesh Rathore ◽  
Wan-Hui Zhang ◽  
Joseph E. Mazurkiewicz ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Pulmonary Artery ◽  
Smooth Muscle Cells ◽  
Calcium Release ◽  
Gene Knockout ◽  
Ryanodine Receptors ◽  
Muscle Cells ◽  
Ruthenium Red ◽  
Pulmonary Artery Smooth Muscle ◽  
Isolated Rat

In this study we examined the expression of RyR subtypes and the role of RyRs in neurotransmitter- and hypoxia-induced Ca2+ release and contraction in pulmonary artery smooth muscle cells (PASMCs). Under perforated patch clamp conditions, maximal activation of RyRs with caffeine or inositol triphosphate receptors (IP3Rs) with noradrenaline induced equivalent increases in [Ca2+]i and Ca2+-activated Cl− currents in freshly isolated rat PASMCs. Following maximal IP3-induced Ca2+ release, neither caffeine nor chloro-m-cresol induced a response, whereas prior application of caffeine or chloro-m-cresol blocked IP3-induced Ca2+ release. In cultured human PASMCs, which lack functional expression of RyRs, caffeine failed to affect ATP-induced increases in [Ca2+]i in the presence and absence of extracellular Ca2+. The RyR antagonists ruthenium red, ryanodine, tetracaine, and dantrolene greatly inhibited submaximal noradrenaline– and hypoxia-induced Ca2+ release and contraction in freshly isolated rat PASMCs, but did not affect ATP-induced Ca2+ release in cultured human PASMCs. Real-time quantitative RT-PCR and immunofluorescence staining indicated similar expression of all three RyR subtypes (RyR1, RyR2, and RyR3) in freshly isolated rat PASMCs. In freshly isolated PASMCs from RyR3 knockout (RyR3−/−) mice, hypoxia-induced, but not submaximal noradrenaline–induced, Ca2+ release and contraction were significantly reduced. Ruthenium red and tetracaine can further inhibit hypoxic increase in [Ca2+]i in RyR3−/− mouse PASMCs. Collectively, our data suggest that (a) RyRs play an important role in submaximal noradrenaline– and hypoxia-induced Ca2+ release and contraction; (b) all three subtype RyRs are expressed; and (c) RyR3 gene knockout significantly inhibits hypoxia-, but not submaximal noradrenaline–induced Ca2+ and contractile responses in PASMCs.

scholarly journals Free radical production in hypoxic pulmonary artery smooth muscle cells

2000 ◽  
Vol 279 (2) ◽  
pp. L408-L412 ◽  
Author(s):  
David W. Killilea ◽  
Raymond Hester ◽  
Ronald Balczon ◽  
Pavel Babal ◽  
Mark N. Gillespie
Keyword(s):  
Smooth Muscle ◽  
Free Radical ◽  
Pulmonary Artery ◽  
Smooth Muscle Cells ◽  
Main Pulmonary Artery ◽  
Muscle Cells ◽  
Exposure System ◽  
Free Radical Production ◽  
Radical Production ◽  
Pulmonary Artery Smooth Muscle

This study used an inexpensive and versatile environmental exposure system to test the hypothesis that hypoxia promoted free radical production in primary cultures of rat main pulmonary artery smooth muscle cells (PASMCs). Production of reactive species was detected by fluorescence microscopy with the probe 2′,7′-dichlorodihydrofluorescein, which is converted to the fluorescent dichlorofluorescein (DCF) in the presence of various oxidants. Flushing the airspace above the PASMC cultures with normoxic gas (20% O2, 75% N2, and 5% CO2) resulted in stable Po 2 values of ∼150 Torr, whereas perfusion of the airspace with hypoxic gas (0% O2, 95% N2, and 5% CO2 ) was associated with a reduction in Po 2 values to stable levels of ∼25 Torr. Hypoxic PASMCs became increasingly fluorescent at ∼500% above the normoxic baseline after 60 min. Hypoxia-induced DCF fluorescence was attenuated by the addition of the antioxidants dimethylthiourea and catalase. These findings show that PASMCs acutely exposed to hypoxia exhibit a marked increase in intracellular DCF fluorescence, suggestive of reactive oxygen or nitrogen species production.

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