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Beta-adrenergic and muscarinic receptor mRNA accumulation in the sinoatrial node area of adult and senescent rat hearts.

Authors
Hardouin-S; Bourgeois-F; Toraasson-M; Oubenaissa-A; Elalouf-JM; Fellmann-D; Dakhli-T; Swynghedauw-B; Moalic-JM
Source
Mech Ageing Dev 1998 Feb; 100(3):277-297
NIOSHTIC No.
20027956
Abstract
The sinoatrial (SA) node is the cardiac pacemaker and changes in its adrenergic-muscarinic phenotype have been postulated as a determinant of age-associated modifications in heart rate variability. To address this question, right atria were microdissected, the SA node area was identified by acetylcholinesterase staining, and, using a RT-PCR method, the accumulation of mRNA molecules encoding beta1- and beta2-adrenergic (beta1- and beta2-AR) and muscarinic (M2-R) receptor was quantified to define the proportion between beta-AR and M2-R mRNAs within the sinoatrial area of adult (3 months) and senescent (24 months) individual rat hearts. In adult hearts, the highest M2-R/beta-AR mRNA ratio was observed within the sinoatrial area compared with adjacent atrial myocardium, while in the senescent hearts, no difference was observed between sinoatrial and adjacent areas. This change was specific of the sinoatrial area since adult and senescent whole atrial or ventricular myocardium did not differ in their M2-R/beta-AR mRNA ratio, and was associated with a fragmentation of acetylcholinesterase staining of the senescent SA node. Quantitative changes in the expression of genes encoding proteins involved in heart rate regulation specifically affect the sinoatrial area of the senescent heart.
Keywords
Laboratory-animals; Animals; Animal-studies; Heart; Quantitative-analysis; Genes; Heart-rate; Cardiovascular-disease; Cardiovascular-system; Cardiovascular-system-disease; Cardiovascular-function
CODEN
MAGDA3
Publication Date
19980216
Document Type
Journal Article
Fiscal Year
1998
NTIS Accession No.
NTIS Price
Issue of Publication
3
ISSN
0047-6374
NIOSH Division
DBBS
Source Name
Mechanisms of Ageing and Development
State
OH
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