Myocardial ATP levels are depressed following global ischemia (ISC) and require 9-10 days for recovery(REC). We have been investigating the role played by ATP precursor loss in prolonged REC. In previous studies adenine and ribose(R) enhanced ATP REC to 86% by 24° after ISC. This study attempted to identify the rate limiting step in ATP REC by providing R alone. Dogs on cardiopulmonary bypass (CPB) were subjected to 20′ of normothermic ISC, weaned from CPB, and followed for 24°. Following ISC and for 24°, either R(80 mM) or normal saline (NS) was infused (1 ml/min). LV biopsies were analyzed for adenine nucleotide content (table). Cardiac output (CO), LV and renal blood flows(BF) were measured (radioactive microspheres).
In both groups, ATP fell 50% at 20′ ISC. There was no ATP recovery by 24° in S dogs. In R dogs, however, ATP was 90% of control, and the energy charge (EC=ATP+½ADP/ATP+ADP+AMP) was 96% of control. LV and renal BF were similar in NS and R dogs. CO, however, was increased in R dogs (204±16 vs 142±13 ml/min/kg, p<0.05). We conclude: recovery of ATP following global ISC ±s accelerated by R, and R may be the most essential ATP precursor. (*p<0.01)