1. Opioid preconditioning: myocardial function and energy metabolism
Daniel C Sigg, MD, James A Coles, MS, William J Gallagher, BS, Peter R Oeltgen, PhD, Paul A Iaizzo, PhD 
The Annals of Thoracic Surgery 
Volume 72, Issue 5, Pages (November 2001)
DOI: /S (01)

2. Fig 1
Shown are indexed cardiac outputs (per kilogram of body weight) of isolated hearts reperfused after 75 minutes of cold-ischemic storage. Hearts pretreated in vivo with either morphine sulfate or d-Ala2, d-Leu5-enkephalin (DADLE) showed higher cardiac outputs after 1 hour of functioning in working mode (controls, p < 0.05 vs morphine, one-way analysis of variance; p < 0.05 vs 0 hours, repeated measures analysis of variance), whereas immediately on initiation of working mode perfusion, no significant differences were detected among opioid-preconditioned and control hearts. The smaller figure shows that the in vivo preischemic cardiac outputs (per kilogram of body weight), obtained just before the ischemic period, were comparable among groups. (CO/kg = cardiac output per kilogram of body weight.)
The Annals of Thoracic Surgery  , DOI: ( /S (01) )

3. Fig 2
Left ventricular relaxation time constant (tau) and left ventricular cardiac outputs (per kilogram of body weight) of isolated working hearts pretreated in vivo with 1 mg/kg d-Ala2, d-Leu5enkephalin are shown. The interval between drug infusion and hypothermic ischemia (75 minutes) was only 15 minutes in these two additional animals (as opposed to 2 hours in the main treatment groups).
The Annals of Thoracic Surgery  , DOI: ( /S (01) )

4. Fig 3
High-energy phosphates from left atrial biopsy specimens were determined by high-performance liquid chromatography to calculate the energy charge (EC) of the adenylate pool, which was calculated as follows: ATP+(0.5×adenosine diphosphate)/(ATP+adenosine diphosphate+adenosine monophosphate). The energy charge was better preserved at the end of cold ischemia in hearts preconditioned with morphine sulfate or d-Ala2, d-Leu5-enkephalin (DADLE), whereas in controls there was a significant decrease (p < 0.05, repeated measures analysis of variance, Bonferroni post hoc test). Furthermore, by direct group comparison, the energy charge was significantly higher in the DADLE-treated group compared with the saline-treated group at end-ischemia (p < 0.05, one-way analysis of variance, Bonferroni). However, on reperfusion, no significant differences were detected among groups, except that the DADLE-treated group had significantly lower energy charge on reperfusion at 15 minutes compared with in vivo and with end-ischemia (repeated measures analysis of variance, Bonferroni).
The Annals of Thoracic Surgery  , DOI: ( /S (01) )