TY - JOUR
T1 - Regulation of myocyte contraction via neuronal nitric oxide synthase
T2 - Role of ryanodine receptor S-nitrosylation
AU - Wang, Honglan
AU - Viatchenko-Karpinski, Serge
AU - Sun, Junhui
AU - Györke, Inna
AU - Benkusky, Nancy A.
AU - Kohr, Mark J.
AU - Valdivia, Héctor H.
AU - Murphy, Elizabeth
AU - Györke, Sandor
AU - Ziolo, Mark T.
PY - 2010/8
Y1 - 2010/8
N2 - The sarcoplasmic reticulum (SR) Ca 2+ release channel (ryanodine receptor, RyR2) has been proposed to be an end target of neuronal nitric oxide synthase (NOS1) signalling. The purpose of this study is to investigate the mechanism of NOS1 modulation of RyR2 activity and the corresponding effect on myocyte function. Myocytes were isolated from NOS1 knockout (NOS1 -/-) and wild-type mice. NOS1 -/- myocytes displayed a decreased fractional SR Ca 2+ release, NOS1 knockout also led to reduced RyR2 S-nitrosylation levels. RyR2 channels from NOS1 -/- hearts had decreased RyR2 open probability. Additionally, knockout of NOS1 led to a decrease in [ 3H]ryanodine binding, Ca 2+ spark frequency (CaSpF) and a rightward shift in the SR Ca 2+ leak/load relationship. Similar effects were observed with acute inhibition of NOS1. These data are indicative of decreased RyR2 activity in myocytes with NOS1 knockout or acute inhibition. Interestingly, the NO donor and nitrosylating agent SNAP reversed the depressed RyR2 open probability, the reduced CaSpF, and caused a leftward shift in the leak/load relationship in NOS1 -/- myocytes. SNAP also normalized Ca 2+ transient and cell shortening amplitudes and SR fractional release in myocytes with NOS1 knockout or acute inhibition. Furthermore, SNAP was able to normalize the RyR2 S-nitrosylation levels. These data suggest that NOS1 signalling increases RyR2 activity via S-nitrosylation, which contributes to the NOS1-induced positive inotropic effect. Thus, RyR2 is an important end target of NOS1.
AB - The sarcoplasmic reticulum (SR) Ca 2+ release channel (ryanodine receptor, RyR2) has been proposed to be an end target of neuronal nitric oxide synthase (NOS1) signalling. The purpose of this study is to investigate the mechanism of NOS1 modulation of RyR2 activity and the corresponding effect on myocyte function. Myocytes were isolated from NOS1 knockout (NOS1 -/-) and wild-type mice. NOS1 -/- myocytes displayed a decreased fractional SR Ca 2+ release, NOS1 knockout also led to reduced RyR2 S-nitrosylation levels. RyR2 channels from NOS1 -/- hearts had decreased RyR2 open probability. Additionally, knockout of NOS1 led to a decrease in [ 3H]ryanodine binding, Ca 2+ spark frequency (CaSpF) and a rightward shift in the SR Ca 2+ leak/load relationship. Similar effects were observed with acute inhibition of NOS1. These data are indicative of decreased RyR2 activity in myocytes with NOS1 knockout or acute inhibition. Interestingly, the NO donor and nitrosylating agent SNAP reversed the depressed RyR2 open probability, the reduced CaSpF, and caused a leftward shift in the leak/load relationship in NOS1 -/- myocytes. SNAP also normalized Ca 2+ transient and cell shortening amplitudes and SR fractional release in myocytes with NOS1 knockout or acute inhibition. Furthermore, SNAP was able to normalize the RyR2 S-nitrosylation levels. These data suggest that NOS1 signalling increases RyR2 activity via S-nitrosylation, which contributes to the NOS1-induced positive inotropic effect. Thus, RyR2 is an important end target of NOS1.
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U2 - 10.1113/jphysiol.2010.192617
DO - 10.1113/jphysiol.2010.192617
M3 - Article
C2 - 20530114
AN - SCOPUS:77956525999
SN - 0022-3751
VL - 588
SP - 2905
EP - 2917
JO - Journal of Physiology
JF - Journal of Physiology
IS - 15
ER -