• Title, Summary, Keyword: Ryanodine receptor

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Thyroid Hormone-Induced Alterations of Ryanodine and Dihydropyridine Receptor Protein Expression in Rat Heart

  • Kim, Hae-Won;Park, Mi-Young;Lee, Eun-Hee;Cho, Hyoung-Jin;Lee, Hee-Ran
    • The Korean Journal of Physiology and Pharmacology
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    • v.3 no.3
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    • pp.329-337
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    • 1999
  • Thyroid hormone-induced cellular dysfunctions may be associated with changes in the intracellular $Ca^{2+}$ concentration. The ryanodine receptor, a $Ca^{2+}$ release channel of the SR, is responsible for the rapid release of $Ca^{2+}$ that activates cardiac muscle contraction. In the excitation-contaction coupling cascade, activation of ryanodine receptors is initiated by the activity of sarcolemmal $Ca^{2+}$ channels, the dihydropyridine receptors. In hyperthyroidism left ventricular contractility and relaxation velocity were increased, whereas these parameters were decreased in hypothyroidism. The mechanisms for these changes have been suggested to include alterations in the expression and/or activity levels of various proteins. In the present study, quantitative changes of ryanodine receptors and the dihydropyridine receptors, and the functional consequences of these changes in various thyroid states were investigated. In hyperthyroid hearts, $[^3H]ryanodine$ binding and ryanodine receptor mRNA levels were increased, but protein levels of ryanodine were not changed significantly. However, the above parameters were markedly decreased in hypothyroid hearts. In case of dihydropyridine receptor, there were a significant increase in the mRNA and protein levels, and [3H]nitrendipine binding, whereas no changes were observed in these parameters of hypothyroid hearts. Our findings indicate that hyperthyroidism is associated with increases in ryanodine receptor and dihydropyridine receptor expression levels, which is well correlated with the ryanodine and dihydropyridine binding. Whereas opposite changes occur in ryanodine receptor of the hypothyroid hearts.

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Characterization of the Ryanodine Receptor and SERCA in Fetal, Neonatal, and Adult Rat Hearts

  • Ramesh, Venkat;Kresch, Mitchell J.;Park, Woo-Jin;Kim, Do-Han
    • BMB Reports
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    • v.34 no.6
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    • pp.573-577
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    • 2001
  • The mammalian heart is known to undergo significant mechanical changes during fetal and neonatal development. The objective of this study was to define the ontogeny of the ryanodine receptor/$Ca^{2+}$ release channel and SERCA that play the major roles in excitation-contraction coupling. Whole ventricular homogenates of fetal (F) (19 and 22 days in gestation), postnatal (N) (1 and 7 days postnatal), and adult (A) (5 weeks postnatal) Sprague-Dawley rat hearts were used to study [$^3H$]ryanodine binding and oxalate-supported $^{45}Ca^{2+}$ uptake. For the ryanodine receptor, the major findings were: (1) The ryanodine receptor density, as determined by maximal [$^3H$]ryanodine binding ($B_{max}$), increased 3 fold between the F22 and A periods ($0.26{\pm}0.1$ vs. $0.73{\pm}0.07$ pmoles/mg protein, p<0.01), whereas there was no significant change during the F22 and N1 development phases ($0.26{\pm}0.1$ vs. $0.34{\pm}0.01$). (2) Affinity of the ryanodine receptor to ryanodine did not significantly change, as suggested by the lack of change in the $K_d$ during the development and maturation. For SERCA, changes started early with an increased rate of $Ca^{2+}$ uptake in the fetal periods (F19: $8.1{\pm}1.1$ vs. F22: $19.3{\pm}2.2$ nmoles/g protein/min; p<0.05) and peaked by 7 days (N7) of the postnatal age ($34.9{\pm}2.1$). Thus, we conclude that the quantitative changes occur in the ryanodine receptor during myocardial development. Also, the maturation of the $Ca^{2+}$ uptake appears to start earlier than that of the $Ca^{2+}$ release.

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Unchanged Protein Level of Ryanodine Receptor but Reduced $[^3H]$ Ryanodine Binding of Cardiac Sarcoplasmic Reticulum from Diabetic Cardiomyopathy Rats

  • Lee, Eun-Hee;Seo, Young-Ju;Kim, Young-Hoon;Kim, Hae-Won
    • The Korean Journal of Physiology and Pharmacology
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    • v.5 no.5
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    • pp.397-405
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    • 2001
  • The ryanodine receptor, a $Ca^{2+}$ release channel of the sarcoplasmic reticulum (SR), is responsible for the rapid release of $Ca^{2+}$ that activates cardiac muscle contraction. In the excitation-contraction coupling cascade, activation of SR $Ca^{2+}$ release channel is initiated by the activity of sarcolemmal $Ca^{2+}$ channels, the dihydropyridine receptors. Previous study showed that the relaxation defect of diabetic heart was due to the changes of the expressional levels of SR $Ca^{2+}$ATPase and phospholamban. In the diabetic heart contractile abnormalities were also observed, and one of the mechanisms for these changes could include alterations in the expression and/or activity levels of various $Ca^{2+}$ regulatory proteins involving cardiac contraction. In the present study, underlying mechanisms for the functional derangement of the diabetic cardiomyopathy were investigated with respect to ryanodine receptor, and dihydropyridine receptor at the transcriptional and translational levels. Quantitative changes of ryanodine receptors and the dihydropyridine receptors, and the functional consequences of those changes in diabetic heart were investigated. The levels of protein and mRNA of the ryanodine receptor in diabetic rats were comparable to these of the control. However, the binding capacity of ryanodine was significantly decreased in diabetic rat hearts. Furthermore, the reduction in the binding capacity of ryanodine receptor was completely restored by insulin. This result suggests that there were no transcriptional and translational changes but functional changes, such as conformational changes of the $Ca^{2+}$ release channel, which might be regulated by insulin. The protein level of the dihydropyridine receptor and the binding capacity of nitrendipine in the sarcolemmal membranes of diabetic rats were not different as compared to these of the control. In conclusion, in diabetic hearts, $Ca^{2+}$ release processes are impaired, which are likely to lead to functional derangement of contraction of heart. This dysregulation of intracellular $Ca^{2+}$ concentration could explain for clinical findings of diabetic cardiomyopathy and provide the scientific basis for more effective treatments of diabetic patients. In view of these results, insulin may be involved in the control of intracellular $Ca^{2+}$ in the cardiomyocyte via unknown mechanism, which needs further study.

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Inhibitory Effect of $Mg^{2+}$ on the Release of $Ca^{2+}$ from Ryanodine Receptor of the Sarcoplasmic Reticulum in the Skeletal Muscle (골격근 망상체 $Ca^{2+}$유리 Channel[Raynodine receptor]의 $Mg^{2+}$에 의한 유리 억제)

  • 이철주
    • The Korean Journal of Thoracic and Cardiovascular Surgery
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    • v.25 no.4
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    • pp.347-355
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    • 1992
  • The precise mechanism of the Excitation-Contraction Coupling is still uncertain. But the concept that Ca2+ induced Ca2+ release [CICR] from the Ryanodine receptor in the sarcoplasmic reticulum [foot structure] may play a major role in E-C coupling has been widely accepted since 1970`s. It is believed that increased cytosolic Ca2+ followed by CICR is main contributor for E-C coupling of striated muscle. Resulting phenomena of ischemic /post-reperfusion myocyte is increased cytosolic Ca2+, even to the absence of Ca2+ in reperfusate. So intracellular inhibitor to CICR might prevent the ischemic and reperfusion damage of myocardial cells. The relatively purified foot protein, especially heavy sarcoplasmic reticulum rich, of the skeletal muscle was incorporated into the black lipid bilayer [Phosphatidyl ethanolamine: Phosphatidyl serine=l: 1]. Under the steady state of membrane potential [+20 mV], ionic current through Ryanodine receptor was measured with Cs+ as charge carrier. In the cis chamber [Cytoplasmic side], Mg2+ strongly inhibited CICR of Ryanodine receptor[Kd=6.2 nM]. In conclusion, naturally existing intracellular free Mg2+ can inhibit CICR from intracellular Ca2+ reservior [heavy SR]. So post-ischemic or post-reperfusing myocardium could be preserved using additional free Mg2+ in cardioplegic solution or reperfusate, otherwise the optimal concentration is undetermined.

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[${^3H}Ryanodine$ Binding Sites of SR Vesicles of the Chicken Pectoral Muscle

  • Yun, Hyo-Yung;Jeon, Jong-Rye;Hong, Jang-Hee;Hur, Gang-Min;Lee, Jae-Heun;Seok, Jeong-Ho
    • The Korean Journal of Physiology and Pharmacology
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    • v.1 no.4
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    • pp.377-384
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    • 1997
  • To investigate the properties of ryanodine binding sites of the bird skeletal SR vesicles, SDS PAGE, purification of RyR, and $[^3H]ryanodine$ binding study were carried out in the SR vesicles prepared from the chicken pectoral muscle. The chicken SR vesicles have two high molecular weight (HMW) protein bands as in eel SR vesicles on SDS PAGE. The HMW bands on SDS PAGE were found in the $[^3H]ryanodine$ peak fraction $(Fr_{3-5})$ obtained from the purification step of the ryanodine receptor protein. Bmax and KD of the chicken $[^3H]ryanodine$ binding sites were 12.52 pmol/mg protein and 14.53 nM, respectively. Specific $[^3H]ryanodine$ binding was almost maximal at $50{\sim}100$ ${\mu}M$ $Ca^{2+}$, but was not increased by 5 mM AMP and not inhibited by high $Ca^{2+}$. Binding was significantly inhibited by $20{\sim}100$ ${\mu}M$ ruthenium red and 1 mM tetracaine, but slightly inhibited by $Mg^{2+}$. From the above results, it is suggested that chicken SR vesicles have the ryanodine binding sites to which the binding of ryanodine is almost maximal at $50{\sim}10$ ${\mu}M$ $Ca^{2+}$, is significantly inhibited by ruthenium red and tetracaine, slightly inhibited by $Mg^{2+}$, but not affected by AMP and not inhibited by high $Ca^{2+}$.

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Effect of Ginseng Components on Ryanodine Receptor-$Ca^{2+}$ Release Channel Complex Protein in Sarcoplasmlc Reticulum of Skeletal Muscle (근 소포체 Ryanodine Receptor-$Ca^{2+}$Release Channel Complex Protein에 미치는 인삼 성분의 영향)

  • 이희봉;한병돈;권상옥
    • Journal of Ginseng Research
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    • v.20 no.3
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    • pp.274-283
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    • 1996
  • In this study, the effects of red ginseng components [ginsenosides (total saponins and $Rg_1$) on the function of ryanodine receptor (RyR) -$Ca^{2+}$ release channel complex protein (named as RyR or $Ca^{2+}$ channel), a membrane protein in sarcoplasmic reticulum (SR) of rabbit skeletal muscle were examined at the SR vesicle's level and the molecular levels with Chaps-solubilized and purified $Ca^{2+}$ channel protein and with reconstituted proteoliposomes by dialysis. The results were as follows. 1. The binding of ryanodine known as inhibitor of muscle contraction to the RyR was decreased at the whole range of concentration ($10^2$~$10^7$%) by these two ginseng components. In heavy SR vesicles, Chaps-solubilized and purified $Ca^{2+}$ channel protein, and reconstituted vesicles, its maximal inhibition by total saponins was shown at the concentration of $10^3$, $10^3$%, and $10^5$% respectively, and by gin- senoside $Rg_1}$) each was $10^3$%, $10^3$%, and $10^4$%. 2. The release of $Ca^{2+}$ ion through $Ca^{2+}$ channel in heavy SR vesicles and reconstituted proteoliposomes was increased as a whole by these two ginseng components, and particularly maximal release by both of them was shown at the range of $10^4$~$10^6$%. These results were seemed to be caused by conformational change of $Ca^{2+}$ release channel protein (RyR) by red ginseng components [ginsenosides (total saponins and $Rg_1}$).

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Detection of Porcine Stress Syndrome from Genomic DNA of Hair Follicle by PCR-RFLP in Breeding Pig (종돈의 모근 Genomic DNA를 이용한 스트레스 증후군 검색)

  • 김계웅;김진우;유재영;박홍양
    • Reproductive and Developmental Biology
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    • v.28 no.1
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    • pp.37-43
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    • 2004
  • This study was carried out to investigate PSS (Porcine Stress Syndrome) with the PSE (Pale, Soft, Exudative) in 319 different pigs(Yorkshire 150; Landrace 89 and Duroc 80). The PCR-RFLP method was adapted to detect the ryanodine receptor (RYR 1) gene mutation and to estimate the genotype frequency of the RYR1 gene in breeding pig population. The DNA samples were collected from hair follicles of pigs of Yorkshire, Landrace and Duroc. After DNA amplification by PCR, the PCR products were digested by restriction enzyme, Cfo I. Primary PCR products of ryanodine receptor gene were length of 659 bp in hair follicle and their second PCR products were length of 522 bp in hair follicle. The exon region (522 bp) including point mutation ($C \arrow T; Arg \arrow Cys$) in the porcine ryanodine receptor gene, which is a causal mutation for PSS, was digested with Cfo I restriction enzyme. The RYR1 gene was classifed into three genotypes by agarose gel electrophoresis. The normal homozygous (NN) individuals showed two DNA fragments consisted of 439 and 83 bp. The mutant homozygous (nn) individuals showed only one DNA fragment 522 bp. In addition, all three fragments (522, 439 and 83 bp) were showed in heterozygous (Nn) carrier animals. The normal homozygous (NN), heterozygous (Nn) and mutant homozygous (nn) were 98.00, 2.00 and 0.00% in Yorkshire pigs, 87.64, 11.24 and 1.12% in Landrace, 100.00, 0.00 and 0.00% in Duroc, respectively. The gene frequencies of N and n were 0.990 and 0.010 in Yorkshire pigs, 0.933 and 0.067 in Landrace, 1.000 and 0.000 in Duroc, respectively.

Functional and Immunological Properties of Ryanodine Receptor in the Eel Skeletal Muscle (뱀장어 근육내 Ryanodine Receptor의 기능 및 면역학적 성질)

  • Seok, Jeong-Ho;Lee, Yeon-Soo;Nam, Jang-Hyeon;Choi, Suk-Jeong;Hong, Jang-Hee;Lee, Jae-Heun
    • The Korean Journal of Pharmacology
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    • v.31 no.2
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    • pp.207-217
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    • 1995
  • To investigate the functional and immunological properties of the Ca-release channel in the sarcoplasmic reticulum(SR) of the eel skeletal muscle, $[^3H]ryanodine$ binding, SDS gel electrophoresis, $^{45}Ca\;release$ studies, and immunoblot assay were carried out in the SR of the eel skeletal muscle. Maximal binding sites(Bmax) and $K_D$ values of $[^3H]ryanodine$ for Ca-release channel of the SR of the eel skeletal muscle were $19.44{\pm}1.40\;pmole/mg$ protein and $15.55{\pm}1.69\;nM$, respectively. $[^3H]Ryanodine$ binding to RyR was increased by calcium and AMP. The SR of the eel skeletal muscle has two high molecular weight bands on the SDS PAGE. The mobility of upper band was more slower than the single band of the rabbit skeletal muscle, and that of the lower band was similar with the single band of canine cardiac muscle. Vesicular $^{45}Ca-release$ was activated by calcium. Ca-induced $^{45}Ca-release$ was significantly inhibited by $MgCl_2(2\;mM)$, ruthenium red$(10\;{/mu}M)$ or tetracaine(1 mM), but not by high concentration of calcium itself. AMP-induced $^{45}Ca-release$ was slightly occurred only in the absence of calcium, it was not inhibited by $MgCl_2$ or ruthenium red. Caffeine also increased $^{45}Ca-release$ from the SR vesicles, but it was not affected by $MgCl_2$ or ruthenium red. Polyclonal Ab against rat skeletal muscle RyR is reacted with that of rabbit, but not reacted with that of the eel skeletal muscle. These results suggested that ryanodine receptor of the SR of the eel skeletal muscle is showing some similar properties with that of mammalian skeletal muscle, but might be an another isotype channel having two bands which is less sensitive to AMP, not cross-reacted with antisera against rat RyR, and not inhibited by high concentration of calcium.

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Reconstitution of Sarcoplasmic Reticulum-$Ca^{2+}$ Release Channels into Phospholipid Vesicles : Investigation of Conditions for Functional Reconstitution

  • Yang, In-Sik;Lee, Hee-Bong
    • BMB Reports
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    • v.28 no.2
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    • pp.129-137
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    • 1995
  • The ryanodine-receptor $Ca^{2+}$ release channel protein in the sarcoplasmic reticulum membrane of rabbit skeletal muscle plays an important role in muscle exitation-contraction (E-C) coupling. Various types of detergents were tested, including Chaps, cholate, octylglucoside, Zwittergents, Mega-9, Lubrol PX, and Triton X-100 for solubilization of this protein. Among these, Chaps and Triton X-100 were found to optionally solubilize the channel complex. Optimum conditions for this solubilization were pH 7.4 with a salt concentration of 1 M. The addition of phospholipid in the solubilization step helped in stabilizing the protein. The purification of the receptor was performed using sucrose density gradient centrifugation. Various methods [dilution, freeze-thaw, adsorption (Biobeads), and dialysis] were investigated to incorporate the Chaps-solubilized and purified $Ca^{2+}$ release channel protein into liposomes made from different types of phospholipids. Of these, a combined method consisting of a dialysis, freeze-thaw and sonication steps yielded the best results. Reconstituted vesicles produced by this method with 95% phosphatidylcholine (from soybean extract) had good function.

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[$Na^+-Ca^{2+}$ Exchange Curtails $Ca^{2+}$before Its Diffusion to Global $Ca^{2+}{_i}$ in the Rat Ventricular Myocyte

  • Ahn, Sung-Wan;Ko, Chang-Mann
    • The Korean Journal of Physiology and Pharmacology
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    • v.9 no.2
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    • pp.95-101
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    • 2005
  • In the heart, $Na^{+}-Ca^{2+}$ exchange (NCX) is the major $Ca^{2+}$ extrusion mechanism. NCX has been considered as a relaxation mechanism, as it reduces global $[Ca^{2+}]_i$ raised during activation. However, if NCX locates in the close proximity to the ryanodine receptor, then NCX would curtail $Ca^{2+}$ before its diffusion to global $Ca^{2+}_i$ This will result in a global $[Ca^{2+}]_i$ decrease especially during its ascending phase rather than descending phase. Therefore, NCX would decrease the myocardial contractility rather than inducing relaxation in the heart. This possibility was examined in this study by comparing NCX-induced extrusion of $Ca^{2+}$ after its release from SR in the presence and absence of global $Ca^{2+}_i$ transient in the isolated single rat ventricular myocytes by using patch-clamp technique in a whole-cell configuration. Global $Ca^{2+}_i$ transient was controlled by an internal dialysis with different concentrations of BAPTA added in the pipette. During stimulation with a ramp pulse from +100 mV to -100 mV for 200 ms, global $Ca^{2+}_i$ transient was suppressed only mildly, and completely at 1 mmol/L, and 10 mmol/L BAPTA, respectively. In these situations, ryanodine-sensitive inward NCX current was compared using $100{\mu}mol/L$ ryanodine, $Na^+$ depletion, 5 mmol/L $NaCl_2$ and $1{\mu}mol/L$ nifedipine. Surprisingly, the result showed that the ryanodine-sensitive inward NCX current was well preserved after 10 mmol/L BAPTA to 91 % of that obtained after 1 mmol/L BAPTA. From this result, it is concluded that most of the NCX-induced $Ca^{2+}$ extrusion occurs before the $Ca^{2+}$ diffuses to global $Ca^{2+})i$ in the rat ventricular myocyte.