TY - JOUR
T1 - Stability of high-energy phosphates in right ventricle
T2 - Myocardial energetics during right coronary hypotension
AU - Itoya, Masao
AU - Mallet, Robert T.
AU - Gao, Zhi Ping
AU - Williams, Arthur G.
AU - Downey, H. Fred
PY - 1996/7
Y1 - 1996/7
N2 - This study was conducted to determine if mechanisms that reduce right coronary (RC) blood flow (RCBF) and right ventricular (RV) oxygen consumption (MV02) during moderate RC hypotension preserve RV high-energy phosphates. RC arteries of anesthetized dogs were cannulated and perfused with arterial blood supplied by a pressurized extracorporeal circuit. RC perfusion pressure (RCPP) was either kept constant at 100 mmHg or reduced to 60 or 30 mmHg for 20 min followed by a freeze-clamp biopsy of RV. Left ventricular (LV) biopsy was also performed to compare energy metabolism between RV and LV. RCBF and MV̇O2 significantly decreased when RCPP was reduced to 60 mmHg, but RV segment shortening (% SS) was unchanged; ATP, creatine phosphate (CrP) and phosphorylation state of CrP ([CrP]/[Cr][Pi]) did not differ from control values. RV %SS, CrP, and phosphorylation state fell markedly at 30 mmHg RCPP. At 100 mmHg RCPP, CrP phosphorylation state in RV was only 35% of that in LV. These results indicate that RV increases its energetic efficiency without significant changes in high-energy phosphates or CrP phosphorylation state during moderate RC hypotension. Furthermore, the RV myocardium maintains a much lower energy level than LV myocardium, commensurate with its lower energy requirements.
AB - This study was conducted to determine if mechanisms that reduce right coronary (RC) blood flow (RCBF) and right ventricular (RV) oxygen consumption (MV02) during moderate RC hypotension preserve RV high-energy phosphates. RC arteries of anesthetized dogs were cannulated and perfused with arterial blood supplied by a pressurized extracorporeal circuit. RC perfusion pressure (RCPP) was either kept constant at 100 mmHg or reduced to 60 or 30 mmHg for 20 min followed by a freeze-clamp biopsy of RV. Left ventricular (LV) biopsy was also performed to compare energy metabolism between RV and LV. RCBF and MV̇O2 significantly decreased when RCPP was reduced to 60 mmHg, but RV segment shortening (% SS) was unchanged; ATP, creatine phosphate (CrP) and phosphorylation state of CrP ([CrP]/[Cr][Pi]) did not differ from control values. RV %SS, CrP, and phosphorylation state fell markedly at 30 mmHg RCPP. At 100 mmHg RCPP, CrP phosphorylation state in RV was only 35% of that in LV. These results indicate that RV increases its energetic efficiency without significant changes in high-energy phosphates or CrP phosphorylation state during moderate RC hypotension. Furthermore, the RV myocardium maintains a much lower energy level than LV myocardium, commensurate with its lower energy requirements.
KW - coronary perfusion pressure
KW - creatine phosphate
KW - myocardial oxygen consumption
KW - oxygen utilization efficiency
UR - http://www.scopus.com/inward/record.url?scp=33750828132&partnerID=8YFLogxK
U2 - 10.1152/ajpheart.1996.271.1.h320
DO - 10.1152/ajpheart.1996.271.1.h320
M3 - Article
C2 - 8760191
AN - SCOPUS:33750828132
VL - 271
SP - H320-H328
JO - American Journal of Physiology - Heart and Circulatory Physiology
JF - American Journal of Physiology - Heart and Circulatory Physiology
SN - 0363-6135
IS - 1 40-1
ER -