title: [Comparison of ryanodine binding to cardiac sarcoplasmic reticulum and nuclear envelope of rat].
abstract: OBJECTIVE
  The characteristics of ryanodine receptor in rat cardiac sarcoplasmic reticulum (SR) and nuclear envelope (NE) were studied.
  
  
  METHODS
  Velocity and isopyknic gradient centrifugation was employed to fractionate rat SR and NE. Ryanodine receptor was assayed with [3H] ryanodine saturate binding to the preparations.
  
  
  RESULTS
  The maximal binding (Bmax) and dissociating constant (Kd) of ryanodine receptor in rat cardiac NE were, 1.7% and 60% of those in SR respectively. Phosphorylation in vitro by PKA and PKC increased Bmax of the receptors in SR by 372% and 121%, and augmented those in NE by 221% and 306%, without any effects on Kd.
  
  
  CONCLUSIONS
  Ryanodine receptors were present in rat myocardial NE, with lower density and higher affinity than those located in SR, which can be activated by PKA and PKC.
authors.affiliation: Institute of Cardiovascular Research, First Hospital, Beijing University, Beijing 100034, China.
authors.forename: Pei-Yong
authors.initials: PY
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.forename: Lin-Wang
authors.initials: LW
authors.lastname: Dong
authors.forename: Yong-Zheng
authors.initials: YZ
authors.lastname: Pang
authors.forename: Chao-Shu
authors.initials: CS
authors.lastname: Tang
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D007700:Kinetics; D009206:Myocardium / Q000378:metabolism; D009685:Nuclear Envelope / Q000378:metabolism / Q000502:physiology*; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012433:Ryanodine / Q000378:metabolism*; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism*; D012519:Sarcoplasmic Reticulum / Q000378:metabolism / Q000502:physiology*
chemical_list: D019837:Ryanodine Receptor Calcium Release Channel; D012433:Ryanodine; D002118:Calcium