title: [Effect of serum autoantibodies against the M2 muscarinic acetylcholine receptors from patients with heart failure on L-Type Ca2+ channel activity in guinea pig cardiac myocytes].
abstract: OBJECTIVE
  To investigate the effect of serum autoantibodies against the human M(2) muscarinic acetylcholine receptors (M(2)-receptors, Abs) from patients with congestive heart failure on L-Type Ca(2+) channel activity in guinea pig cardiac myocytes.
  
  
  METHODS
  Using whole cell patch-clamp technique, we quantitatively measured the ionic intensity and density of L-Type Ca(2+) channel (I(Ca-L)).
  
  
  RESULTS
  The M(2)-receptors agonist (carbachol) could decrease the I(Ca-L) peak intensity and density stimulated by isoprenaline from (2111.65 +/- 203.13) pA and (18.83 +/- 1.14) pA/pF to (1230.87 +/- 208.14) pA (P < 0.01) and (10.72 +/- 1.06) pA/pF (P < 0.01). The serum Abs could also decrease I(Ca-L) peak intensity and density [from (1995.21 +/- 195.13) pA and (18.13 +/- 1.03) pA/pF to (636.42 +/- 110.07) pA (P < 0.01) and (5.54 +/- 0.81) pA/pF, P < 0.01]. The M(2)-receptors antagonist, atropine was able to block these effects of carbachol and Abs.
  
  
  CONCLUSIONS
  The circulating serum autoantibodies against the M(2)-receptors has similar effect as M(2)-receptors agonist on decreasing the isoprenaline stimulated I(Ca-L) in guinea pig cardiac myocytes and possess negative inotropic effect. These results further suggest that serum autoantibodies against the human M(2) muscarinic acetylcholine receptors may participate in the pathophysiological processes in patients with heart failure.
authors.affiliation: Department of Internal Medicine, Beijing Chaoyang Hospital, Capital University of Medical Sciences, Beijing 100020, China.
authors.forename: Guo-bin
authors.initials: GB
authors.lastname: Miao
authors.forename: Jin-chun
authors.initials: JC
authors.lastname: Liu
authors.forename: Shu-yan
authors.initials: SY
authors.lastname: Wang
authors.forename: Xiu-lan
authors.initials: XL
authors.lastname: Liu
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D001323:Autoantibodies / Q000494:pharmacology*; D020746:Calcium Channels, L-Type / Q000187:drug effects*; D005260:Female; D006168:Guinea Pigs; D006333:Heart Failure / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism; D018408:Patch-Clamp Techniques; D043585:Receptor, Muscarinic M2 / Q000276:immunology*; D044967:Serum / Q000276:immunology
chemical_list: D001323:Autoantibodies; D020746:Calcium Channels, L-Type; D043585:Receptor, Muscarinic M2