TY - JOUR
T1 - Effects of aging and ischemia on adenosine receptor transcription in mouse myocardium
AU - Ashton, Kevin J.
AU - Nilsson, Ulrika
AU - Willems, Laura
AU - Holmgren, Kirsty
AU - Headrick, John P.
PY - 2003
Y1 - 2003
N2 - The well-documented age-related change in ischemic tolerance may result from impaired adenosine-mediated cardioprotection. Additionally, ischemia itself may potentially modify adenosine signalling, contributing to the post-ischemic phenotype. This study investigates age- and ischemia-dependent changes in adenosine receptor transcript levels (Adora) for the A1, A2A, A2B, and A3 receptor subtypes in mouse myocardium. Hearts from young (2-4 months) and moderately aged (16-18 months) mice were subjected to 20-min ischemia and 45-min reperfusion. Ischemic tolerance was impaired in aged hearts, which recovered less than 30% ventricular pressure development (compared with ∼70% in young hearts), and lost 2-fold higher levels of lactate dehydrogenase during reperfusion (reflecting cellular disruption). Real-time PCR analyses revealed an age-related decline in Adora3 levels and induction of Adora2B. Curiously, this effect was mimicked by ischemia, which acutely reduced Adora3 levels and induced Adora2B in young (but not old) hearts. In contrast, in aged hearts ischemia selectively reduced levels of Adora1 transcript (∼2-fold) without altering transcript levels for the other receptors. These results demonstrate selective modulation of cardioprotective adenosine receptor transcription by both aging and ischemia. Reduced A3 adenosine receptor transcription may contribute to impaired ischemic tolerance in aged hearts, whereas changes in Adora transcription induced by ischemia may impact on the post-ischemic phenotype at later time points.
AB - The well-documented age-related change in ischemic tolerance may result from impaired adenosine-mediated cardioprotection. Additionally, ischemia itself may potentially modify adenosine signalling, contributing to the post-ischemic phenotype. This study investigates age- and ischemia-dependent changes in adenosine receptor transcript levels (Adora) for the A1, A2A, A2B, and A3 receptor subtypes in mouse myocardium. Hearts from young (2-4 months) and moderately aged (16-18 months) mice were subjected to 20-min ischemia and 45-min reperfusion. Ischemic tolerance was impaired in aged hearts, which recovered less than 30% ventricular pressure development (compared with ∼70% in young hearts), and lost 2-fold higher levels of lactate dehydrogenase during reperfusion (reflecting cellular disruption). Real-time PCR analyses revealed an age-related decline in Adora3 levels and induction of Adora2B. Curiously, this effect was mimicked by ischemia, which acutely reduced Adora3 levels and induced Adora2B in young (but not old) hearts. In contrast, in aged hearts ischemia selectively reduced levels of Adora1 transcript (∼2-fold) without altering transcript levels for the other receptors. These results demonstrate selective modulation of cardioprotective adenosine receptor transcription by both aging and ischemia. Reduced A3 adenosine receptor transcription may contribute to impaired ischemic tolerance in aged hearts, whereas changes in Adora transcription induced by ischemia may impact on the post-ischemic phenotype at later time points.
UR - http://www.scopus.com/inward/record.url?scp=0345276471&partnerID=8YFLogxK
U2 - 10.1016/j.bbrc.2003.10.127
DO - 10.1016/j.bbrc.2003.10.127
M3 - Article
C2 - 14637147
AN - SCOPUS:0345276471
SN - 0006-291X
VL - 312
SP - 367
EP - 372
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 2
ER -