首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Calstabin deficiency, ryanodine receptors, and sudden cardiac death   总被引:4,自引:0,他引:4  
Altered cardiac ryanodine receptor (RyR2) function has an important role in heart failure and genetic forms of arrhythmias. RyR2 constitutes the major intracellular Ca2+ release channel in the cardiac sarcoplasmic reticulum (SR). The peptidyl-prolyl isomerase calstabin2 (FKBP12.6) is a component of the RyR2 macromolecular signaling complex. Calstabin2 binding to RyR2 is regulated by PKA phosphorylation of Ser2809 in RyR2. PKA phosphorylation of RyR2 decreases the binding affinity for calstabin2 and increases RyR2 open probability and sensitivity to Ca2+-dependent activation. In heart failure, a majority of studies have found that RyR2 becomes chronically PKA hyper-phosphorylated which depletes calstabin2 from the channel complex. Calstabin2 dissociation causes a diastolic SR Ca2+ leak contributing to depressed intracellular Ca2+ cycling and decreased cardiac contractility. Missense mutations linked to genetic forms of exercise-induced arrhythmias and sudden cardiac death also cause decreased calstabin2-binding affinity and leaky RyR2 channels. We review the importance of calstabin2 for RyR2 function and excitation-contraction coupling, and discuss new observations that implicate dysregulation of calstabin2 binding as a central mechanism for abnormal calcium cycling in heart failure and triggered arrhythmias.  相似文献   

2.
The study of Ca2+ sparks has led to extensive new information regarding the gating of the Ca2+ release channels underlying these events in skeletal, cardiac and smooth muscle cells, as well as the possible roles of these local Ca2+ release events in muscle function. Here we review basic procedures for studying Ca2+sparks in skeletal muscle, primarily from frog, as well as the basic results concerning the properties of these events, their pattern and frequency of occurrence during fiber depolarization and the mechanisms underlying their termination. Finally, we also consider the contribution of different ryanodine receptor (RyR) isoforms to Ca2+ sparks and the number of RyR Ca2+ release channels that may contribute to the generation of a Ca2+ spark. Over the decade since their discovery, Ca2+ sparks have provided a wealth of information concerning the function of Ca2+ release channels within their intracellular environment.  相似文献   

3.
The cardiac ryanodine receptor (RyR2), the major calcium release channel on the sarcoplasmic reticulum (SR) in cardiomyocytes, has recently been shown to be involved in at least two forms of sudden cardiac death (SCD): (1) Catecholaminergic polymorphic ventricular tachycardia (CPVT) or familial polymorphic VT (FPVT); and (2) Arrhythmogenic right ventricular dysplasia type 2 (ARVD2). Eleven RyR2 missense mutations have been linked to these diseases. All eleven RyR2 mutations cluster into 3 regions of RyR2 that are homologous to the three malignant hyperthermia (MH)/central core disease (CCD) mutation regions of the skeletal muscle ryanodine receptor/calcium release channel RyR1. MH/CCD RyR1 mutations have been shown to alter calcium-induced calcium release. Sympathetic nervous system stimulation leads to phosphorylation of RyR2 by protein kinase A (PKA). PKA phosphorylation of RyR2 activates the channel. In conditions associated with high rates of SCD such as heart failure RyR2 is PKA hyperphosphorylated resulting in "leaky" channels. SR calcium leak during diastole can generate "delayed after depolarizations" that can trigger fatal cardiac arrhythmias (e.g., VT). We propose that RyR2 mutations linked to genetic forms of catecholaminergic-induced SCD may alter the regulation of the channel resulting in increased SR calcium leak during sympathetic stimulation.  相似文献   

4.
Ca2+ efflux from the sarcoplasmic reticulum (SR) is routed primarily through SR Ca2+ release channels (ryanodine receptors, RyRs). When clusters of RyRs are activated by trigger Ca2+ influx through L-type Ca2+ channels (dihydropyridine receptors, DHPR), Ca2+ sparks are observed. Close spatial coupling between DHPRs and RyR clusters and the relative insensitivity of RyRs to be triggered by Ca2+ together ensure the stability of this positive-feedback system of Ca2+ amplification. Despite evidence from single channel RyR gating experiments that phosphorylation of RyRs by protein kinase A (PKA) or calcium-calmodulin dependent protein kinase II (CAMK II) causes an increase in the sensitivity of the RyR to be triggered by [Ca2+]i there is little clear evidence to date showing an increase in Ca2+ spark rate. Indeed, there is some evidence that the SR Ca2+ content may be decreased in hyperadrenergic disease states. The question is whether or not these observations are compatible with each other and with the development of arrhythmogenic extrasystoles that can occur under these conditions. Furthermore, the appearance of an increase in the SR Ca2+ “leak” under these conditions is perplexing. These and related complexities are analyzed and discussed in this report. Using simple mathematical modeling discussed in the context of recent experimental findings, a possible resolution to this paradox is proposed. The resolution depends upon two features of SR function that have not been confirmed directly but are broadly consistent with several lines of indirect evidence: (1) the existence of unclustered or “rogue” RyRs that may respond differently to local [Ca2+]i in diastole and during the [Ca2+]i transient; and (2) a decrease in cooperative or coupled gating between clustered RyRs in response to physiologic phosphorylation or hyper-phosphorylation of RyRs in disease states such as heart failure. Taken together, these two features may provide a framework that allows for an improved understanding of cardiac Ca2+ signaling.  相似文献   

5.
Arrhythmias, a common cause of sudden cardiac death, can occur in structurally normal hearts, although the mechanism is not known. In cardiac muscle, the ryanodine receptor (RyR2) on the sarcoplasmic reticulum releases the calcium required for muscle contraction. The FK506 binding protein (FKBP12.6) stabilizes RyR2, preventing aberrant activation of the channel during the resting phase of the cardiac cycle. We show that during exercise, RyR2 phosphorylation by cAMP-dependent protein kinase A (PKA) partially dissociates FKBP12.6 from the channel, increasing intracellular Ca(2+) release and cardiac contractility. FKBP12.6(-/-) mice consistently exhibited exercise-induced cardiac ventricular arrhythmias that cause sudden cardiac death. Mutations in RyR2 linked to exercise-induced arrhythmias (in patients with catecholaminergic polymorphic ventricular tachycardia [CPVT]) reduced the affinity of FKBP12.6 for RyR2 and increased single-channel activity under conditions that simulate exercise. These data suggest that "leaky" RyR2 channels can trigger fatal cardiac arrhythmias, providing a possible explanation for CPVT.  相似文献   

6.
We show that a glutathione transferase (GST) protein, which is recognised by an antibody against the muscle-specific human GSTM2-2 (hGSTM2-2), is associated with the lumen of the sarcoplasmic reticulum (SR) of cardiac muscle, but not skeletal muscle. We further show that hGSTM2-2 modifies both cardiac and skeletal ryanodine receptor (RyR) activity when it binds to the luminal domain of the RyR channel complex. The properties of hGSTM2-2 were compared with those of the calsequestrin (CSQ), a Ca2+ binding protein also present in the lumen of the SR which, like GSTM2-2, contains a thioredoxin-fold structure and modifies RyR activity (Wei, L., Varsanyi, M., Dulhunty, A. F., Beard, N. A. (2006). The Biophysical Journal, 91, 1288–1301). The glutathione transferase activity of hGSTM2-2 is strong, while CSQ is essentially inactive. Conversely CSQ is a strong Ca2+ binder, but hGSTM2-2 is not. The effects of luminal hGSTM2-2 on RyR activity differ from those of CSQ in that hGSTM2-2 activates RyRs by increasing their open probability and conductance and the effects are independent of luminal Ca2+ concentration. The results suggest that GSTM2-2 can interact with specific luminal sites on the RyR complex and that the interaction is likely to be within the pore of the RyR channel. The differences between the effects of CSQ and hGSTM2-2 suggest that the thioredoxin fold is not a major determinant of the luminal actions of either protein. The results indicate that GSTM2-2 is a novel luminal regulator of the RyR channels in the heart.  相似文献   

7.
The adjustment of Ca2+ entry in cardiac cells is critical to the generation of the force necessary for the myocardium to meet the physiological needs of the body. In this review, we present the concept that Ca2+ can promote its own entry through Ca2+ channels by different mechanisms. We refer to it under the general term of ‘Ca2+-induced Ca2+ entry’ (CICE). We review short-term mechanisms (usually termed facilitation) that involve a stimulating effect of Ca2+ on the L-type Ca2+ current (ICa-L) amplitude (positive staircase) or a lessening of Ca2+-dependent inactivation of ICa-L. This latter effect is related to the amount of Ca2+ released by ryanodine receptors (RyR2) of the sarcoplasmic reticulum (SR). Both effects are involved in the control of action potential (AP) duration. We also describe a long-term mechanism based on Ca2+-dependent down-regulation of the Kv4.2 gene controlling functional expression of the repolarizing transient outward K+ current (Ito) and, thereby, AP duration. This mechanism, which might occur very early during the onset of hypertrophy, enhances Ca2+ entry by maintaining Ca2+ channel activation during prolonged AP. Both Ca2+-dependent facilitation and Ca2+-dependent down-regulation of Ito expression favour AP prolongation and, thereby, promote sustained voltage-gated Ca2+ entry used to enhance excitation–contraction (EC) coupling (with no change in the density of Ca2+ channels per se). These self-maintaining mechanisms of Ca2+ entry have significant functions in remodelling Ca2+ signalling during the cardiac AP. They might support a prominent role of Ca2+ channels in the establishment and progression of abnormal Ca2+ signalling during cardiac hypertrophy and congestive heart failure.  相似文献   

8.
This article reviews the key experiments demonstrating calcium-induced calcium release (CICR) in smooth muscle and contrasts the biophysical and molecular features of coupling between the sarcolemmal (L-type Ca2+ channel) and sarcoplasmic reticulum (ryanodine receptor) Ca2+ channels in smooth and cardiac muscle. Loose coupling refers to the coupling process in smooth muscle in which gating of ryanodine receptors is non-obligate and may occur with a variable delay following opening of the sarcolemmal Ca2+ channels. These features have been observed in the earliest studies of CICR in smooth muscle and are in marked contrast to cardiac CICR, where a close coupling between T-tubular and SR membranes results in tight coupling between the gating events. The relationship between this “loose coupling” and distinct subcellular release sites within smooth muscle cells, termed frequent discharge sites, is discussed.  相似文献   

9.
S-Nitrosylation is a ubiquitous post-translational modification that regulates diverse biologic processes. In skeletal muscle, hypernitrosylation of the ryanodine receptor (RyR) causes sarcoplasmic reticulum (SR) calcium leak, but whether abnormalities of cardiac RyR nitrosylation contribute to dysfunction of cardiac excitation-contraction coupling remains controversial. In this study, we tested the hypothesis that cardiac RyR2 is hyponitrosylated in heart failure, because of nitroso-redox imbalance. We evaluated excitation-contraction coupling and nitroso-redox balance in spontaneously hypertensive heart failure rats with dilated cardiomyopathy and age-matched Wistar-Kyoto rats. Spontaneously hypertensive heart failure myocytes were characterized by depressed contractility, increased diastolic Ca2+ leak, hyponitrosylation of RyR2, and enhanced xanthine oxidase derived superoxide. Global S-nitrosylation was decreased in failing hearts compared with nonfailing. Xanthine oxidase inhibition restored global and RyR2 nitrosylation and reversed the diastolic SR Ca2+ leak, improving Ca2+ handling and contractility. Together these findings demonstrate that nitroso-redox imbalance causes RyR2 oxidation, hyponitrosylation, and SR Ca2+ leak, a hallmark of cardiac dysfunction. The reversal of this phenotype by inhibition of xanthine oxidase has important pathophysiologic and therapeutic implications.  相似文献   

10.
Calmodulin (CaM) association with the cardiac muscle ryanodine receptor (RyR2) regulates excitation–contraction coupling. Defective CaM–RyR2 interaction is associated with heart failure. A novel CaM mutation (CaMF90L) was recently identified in a family with idiopathic ventricular fibrillation (IVF) and early onset sudden cardiac death. We report the first biochemical characterization of CaMF90L. F90L confers a deleterious effect on protein stability. Ca2+-binding studies reveal reduced Ca2+-binding affinity and a loss of co-operativity. Moreover, CaMF90L displays reduced RyR2 interaction and defective modulation of [3H]ryanodine binding. Hence, dysregulation of RyR2-mediated Ca2+ release via aberrant CaMF90L–RyR2 interaction is a potential mechanism that underlies familial IVF.  相似文献   

11.
We investigated the initiation of Ca2+waves underlying triggered propagated contractions (TPCs) occurring in rat cardiac trabeculae under conditions that simulate the functional non-uniformity caused by mechanical or ischemic local damage of the myocardium. A mechanical discontinuity along the trabeculae was created by exposing the preparation to a small constant flow jet of solution with a composition that reduces excitation–contraction coupling in myocytes within that segment. Force was measured and sarcomere length as well as [Ca2+]i were measured regionally. When the jet-contained Caffeine, BDM or Low-[Ca2+], muscle-twitch force decreased and the sarcomeres in the exposed segment were stretched by shortening of the normal regions outside the jet. During relaxation the sarcomeres in the exposed segment shortened rapidly. Short trains of stimulation at 2.5 Hz reproducibly caused Ca2+-waves to rise from the borders exposed to the jet. Ca2+-waves started during force relaxation of the last stimulated twitch and propagated into segments both inside and outside of the jet. Arrhythmias, in the form of non-driven rhythmic activity, were triggered when the amplitude of the Ca2+-wave increased by raising [Ca2+]o. The arrhythmias disappeared when the muscle uniformity was restored by turning the jet off. We have used the four state model of the cardiac cross bridge (Xb) with feedback of force development to Ca2+ binding by Troponin-C (TnC) and observed that the force–Ca2+ relationship as well as the force–sarcomere length relationship and the time course of the force and Ca2+ transients in cardiac muscle can be reproduced faithfully by a single effect of force on deformation of the TnC·Ca complex and thereby on the dissociation rate of Ca2+. Importantly, this feedback predicts that rapid decline of force in the activated sarcomere causes release of Ca2+ from TnC.Ca2+,which is sufficient to initiate arrhythmogenic Ca2+ release from the sarcoplasmic reticulum. These results show that non-uniform contraction can cause Ca2+-waves underlying TPCs, and suggest that Ca2+ dissociated from myofilaments plays an important role in the initiation of arrhythmogenic Ca2+-waves.  相似文献   

12.
Excitation-contraction coupling in both skeletal and cardiac muscle depends on structural and functional interactions between the voltage-sensing dihydropyridine receptor L-type Ca2+ channels in the surface/transverse tubular membrane and ryanodine receptor Ca2+ release channels in the sarcoplasmic reticulum membrane. The channels are targeted to either side of a narrow junctional gap that separates the external and internal membrane systems and are arranged so that bi-directional structural and functional coupling can occur between the proteins. There is strong evidence for a physical interaction between the two types of channel protein in skeletal muscle. This evidence is derived from studies of excitation–contraction coupling in intact myocytes and from experiments in isolated systems where fragments of the dihydropyridine receptor can bind to the ryanodine receptors in sarcoplasmic reticulum vesicles or in lipid bilayers and alter channel activity. Although micro-regions that participate in the functional interactions have been identified in each protein, the role of these regions and the molecular nature of the protein–protein interaction remain unknown. The trigger for Ca2+ release through ryanodine receptors in cardiac muscle is a Ca2+ influx through the L-type Ca2+ channel. The Ca2+ entering through the surface membrane Ca2+ channels flows directly onto underlying ryanodine receptors and activates the channels. This was thought to be a relatively simple system compared with that in skeletal muscle. However, complexities are emerging and evidence has now been obtained for a bi-directional physical coupling between the proteins in cardiac as well as skeletal muscle. The molecular nature of this coupling remains to be elucidated.  相似文献   

13.
Calcium release from the sarcoplasmic reticulum (SR) in cardiac muscle occurs through a specialised release channel, the ryanodine receptor, RyR, via the process of Ca-induced Ca release (CICR). The open probability of the RyR is increased by elevation of cytoplasmic Ca concentration ([Ca(2+)](i)). However, in addition to Ca, other modulators affect the RyR open probability. Agents which increase the RyR opening during systole produce a transient increase of systolic [Ca(2+)](i) followed by a return to the initial level due to a compensating decrease of SR Ca content. Increasing RyR opening during diastole decreases SR Ca content and thereby decreases systolic [Ca(2+)](i). We therefore conclude that potentiation of RyR opening will, if anything, decrease systolic [Ca(2+)](i). The effects of specific examples of modulators of the RyR, such as phosphorylation, metabolic changes, heart failure and polyunsaturated fatty acids, are discussed.  相似文献   

14.
To elucidate the relationship between intracellular free Ca2+ concentration ([Ca2+]i) and Ca2+-signalling by the sarcoplasmic reticulum (SR) in Ca2+-overloaded heart muscle cells, the direct effects of “basal” [Ca2+]i on calcium waves were investigated by altering the membrane potential. When basal inter-calcium wave (BCW) [Ca2+]i was maintained at a high level, (i) calcium waves showed more gradual and more rapidly suppressed increase in [Ca2+]-profile (P < 0.005), and (ii) calcium waves occurred at a significantly higher frequency and velocity (259% and 137%), than when low BCW [Ca2+]i was maintained. Similar investigations on inhibition of the Na+-Ca2+ exchanger, however, showed that membrane potential did not elicit direct effects on calcium waves. These results showed that the elevation of BCW [Ca2+]i per se directly influences Ca2+-signalling in heart muscle cells through non-equilibrated release-restoration Ca2+-handling by the SR.  相似文献   

15.
The ryanodine receptors form the calcium release channel in the membrane of the sarcoplasmic reticulum (SR, the main intracellular Ca2+ store). The importance of ryanodine receptors (RyRs) to cardiac pacemaking and rhythmicity is highlighted by more than 69 mutations, RyR mutations, which underlie arrhythmias and sudden cardiac death. Although most of these mutations lie in cytoplasmic domains, they all cause increased RyR activation by Ca2+ in the SR lumen. Presented here is a review of the mechanisms by which cytoplasmic domains of the RyR can determine luminal activation.  相似文献   

16.
This study investigated the effects of cardiac glycosides on single-channel activity of the cardiac sarcoplasmic reticulum (SR) Ca2+ release channels or ryanodine receptor (RyR2) channels and how this action might contribute to their inotropic and/or toxic actions. Heavy SR vesicles isolated from canine left ventricle were fused with artificial planar lipid bilayers to measure single RyR2 channel activity. Digoxin and actodigin increased single-channel activity at low concentrations normally associated with therapeutic plasma levels, yielding a 50% of maximal effect of approximately 0.2 nM for each agent. Channel activation by glycosides did not require MgATP and occurred only when digoxin was applied to the cytoplasmic side of the channel. Similar results were obtained in human RyR2 channels; however, neither the crude skeletal nor the purified cardiac channel was activated by glycosides. Channel activation was dependent on [Ca2+] on the luminal side of the bilayer with maximal stimulation occurring between 0.3 and 10 mM. Rat RyR2 channels were activated by digoxin only at 1 microM, consistent with the lower sensitivity to glycosides in rat heart. These results suggest a model in which RyR2 channel activation by digoxin occurs only when luminal [Ca2+] was increased above 300 microM (in the physiological range). Consequently, increasing SR load (by Na+ pump inhibition) serves to amplify SR release by promoting direct RyR2 channel activation via a luminal Ca2+-sensitive mechanism. This high-affinity effect of glycosides could contribute to increased SR Ca2+ release and might play a role in the inotropic and/or toxic actions of glycosides in vivo.  相似文献   

17.
Identification of the genetic basis of human diseases linked to dysfunctional free calcium (Ca2+) signaling has triggered an explosion of interest in the functional characterization of the molecular components regulating intracellular Ca2+ homeostasis. There is a growing appreciation of the central role of intracellular ryanodine-sensitive Ca2+ release channel (RyR) regulation in skeletal and cardiac muscle pathologies, including malignant hyperthermia, heart failure, and sudden cardiac death. The use of cloned RyR isoforms and recombinant expression techniques has greatly facilitated the elucidation of the molecular basis of RyR Ca2+ release functionality. This review will focus on the recombinant techniques used in the functional characterization of recombinant RyR isoforms and the insights that these approaches have yielded in unraveling the mechanistic basis of RyR channel functionality.  相似文献   

18.
Calcium-dependent regulation of tension and ATPase activity in permeabilized porcine ventricular muscle was lost after incubation with 10 mM vanadate. After transfer from vanadate to a vanadate-free, low-Ca2+ solution (pCa> 8), the permeabilized muscle produced 84.8% ± 20.1% (± S.D., n=98) of the isometric force elicited by high Ca22+ (pCa 4.5 prior to incubation with vanadate. Transfer back to a high Ca2+ solution elicited no additional force (83.2% ± 18.7% of control force). SDS-PAGE and immunoblot analysis of fibers and solutions demonstrated substantial extraction (>90%) of Troponin I (TnI). Calcium dependence was restored after incubation with solutions containing either whole cardiac troponin or a combination of TnI and troponin C subunits. This reversible extraction of troponin directly demonstrates the role of TnI in the regulation of striated muscle contractility and permits specific substitution of the native TnI with exogenously supplied protein.  相似文献   

19.
Release of Ca2+ from the sarcoplasmic reticulum (SR) drives contractile function of cardiac myocytes. Luminal Ca2+ regulation of SR Ca2+ release is fundamental not only in physiology but also in physiopathology because abnormal luminal Ca2+ regulation is known to lead to arrhythmias, catecholaminergic polymorphic ventricular tachycardia (CPVT), and/or sudden cardiac arrest, as inferred from animal model studies. Luminal Ca2+ regulates ryanodine receptor (RyR)2-mediated SR Ca2+ release through mechanisms localized inside the SR; one of these involves luminal Ca2+ interacting with calsequestrin (CASQ), triadin, and/or junctin to regulate RyR2 function.CASQ2-RyR2 regulation was examined at the single RyR2 channel level. Single RyR2s were incorporated into planar lipid bilayers by the fusion of native SR vesicles isolated from either wild-type (WT), CASQ2 knockout (KO), or R33Q-CASQ2 knock-in (KI) mice. KO and KI mice have CPVT-like phenotypes. We show that CASQ2(WT) action on RyR2 function (either activation or inhibition) was strongly influenced by the presence of cytosolic MgATP. Function of the reconstituted CASQ2(WT)–RyR2 complex was unaffected by changes in luminal free [Ca2+] (from 0.1 to 1 mM). The inhibition exerted by CASQ2(WT) association with the RyR2 determined a reduction in cytosolic Ca2+ activation sensitivity. RyR2s from KO mice were significantly more sensitive to cytosolic Ca2+ activation and had significantly longer mean open times than RyR2s from WT mice. Sensitivity of RyR2s from KI mice was in between that of RyR2 channels from KO and WT mice. Enhanced cytosolic RyR2 Ca2+ sensitivity and longer RyR2 open times likely explain the CPVT-like phenotype of both KO and KI mice.  相似文献   

20.
Modifications in the Ca(2+)-uptake and -release functions of the sarcoplasmic reticulum (SR) may be a major component of the mechanisms underlying thyroid state-dependent alterations in heart rate, myocardial contractility, and metabolism. We investigated the influence of hyperthyroid state on the expression and functional properties of the ryanodine receptor (RyR), a major protein in the junctional SR (JSR), which mediates Ca(2+) release to trigger muscle contraction. Experiments were performed using homogenates and JSR vesicles derived from ventricular myocardium of euthyroid and hyperthyroid rabbits. Hyperthyroidism, with attendant cardiac hypertrophy, was induced by the injection of L-thyroxine (200 microg/kg body wt) daily for 7 days. Western blotting analysis using cardiac RyR-specific antibody revealed a significant increase (>50%) in the relative amount of RyR in the hyperthyroid compared with euthyroid rabbits. Ca(2+)-dependent, high-affinity [(3)H]ryanodine binding was also significantly greater ( approximately 40%) in JSR from hyperthyroid rabbits. The Ca(2+ )sensitivity of [(3)H]ryanodine binding and the dissociation constant for [(3)H]ryanodine did not differ significantly between euthyroid and hyperthyroid hearts. Measurement of Ca(2+)-release rates from passively Ca(2+)-preloaded JSR vesicles and assessment of the effect of RyR-Ca(2+)-release channel (CRC) blockade on active Ca(2+)-uptake rates revealed significantly enhanced (>2-fold) CRC activity in the hyperthyroid, compared with euthyroid, JSR. These results demonstrate overexpression of functional RyR in thyroid hormone-induced cardiac hypertrophy. Relative abundance of RyR may be responsible, in part, for the changes in SR Ca(2+) release, cytosolic Ca(2+) transient, and cardiac systolic function associated with thyroid hormone-induced cardiac hypertrophy.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号