Cardiac muscarinic receptor overexpression in sudden infant death syndrome.
BACKGROUND
Sudden infant death syndrome (SIDS) remains the leading cause of death among infants less than 1 year of age. Disturbed expression of some neurotransmitters and their receptors has been shown in the central nervous system of SIDS victims but no biological abnormality of the peripheral vago-cardiac system has been demonstrated to date. The present study aimed to seek vago-cardiac abnormalities in SIDS victims. The cardiac level of expression of muscarinic receptors, as well as acetylcholinesterase enzyme activity were investigated.


RESULTS
Left ventricular samples and blood samples were obtained from autopsies of SIDS and children deceased from non cardiac causes. Binding experiments performed with [(3)H]NMS, a selective muscarinic ligand, in cardiac membrane preparations showed that the density of cardiac muscarinic receptors was increased as shown by a more than doubled B(max) value in SIDS (n = 9 SIDS versus 8 controls). On average, the erythrocyte acetylcholinesterase enzyme activity was also significantly increased (n = 9 SIDS versus 11 controls).


CONCLUSIONS
In the present study, it has been shown for the first time that cardiac muscarinic receptor overexpression is associated with SIDS. The increase of acetylcholinesterase enzyme activity appears as a possible regulatory mechanism.
Livolsi
Angelo
A
Laboratoire de Neurobiologie et Pharmacologie Cardiovasculaire, Université de Strasbourg, Strasbourg, France.
Niederhoffer
Nathalie
N
Dali-Youcef
Nassim
N
Rambaud
Caroline
C
Olexa
Catherine
C
Mokni
Walid
W
Gies
Jean-Pierre
JP
Bousquet
Pascal
P
D000110:Acetylcholinesterase / Q000378:metabolism; D001344:Autopsy; D016022:Case-Control Studies; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D006321:Heart / Q000503:physiopathology; D006801:Humans; D007223:Infant; D008024:Ligands; D008297:Male; D008954:Models, Biological; D009206:Myocardium / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000378:metabolism*; D013398:Sudden Infant Death / Q000097:blood / Q000209:etiology*
D008024:Ligands; D018377:Neurotransmitter Agents; D011976:Receptors, Muscarinic; D000110:Acetylcholinesterase