Myocardial protection of immature rabbits with an ATP-sensitive K+ channel opener pinacidil.

Abstract

OBJECTIVE:

To investigate the effectiveness of pinacidil, an opener of ATP-sensitive K+ channels, in protecting the myocardium of immature rabbit hearts from ischemic reperfusion injury.

METHODS:

Rabbit hearts underwent 30 min of global normothermic ischemia followed by 30 min of reperfusion on the modified Langendorff apparatus. Fifty-two isolated hearts of 3-4 week-old immature rabbits were divided into 4 groups randomly. During ischemia, 3 different cardioplegic solutions were administered intermittently by infusion every 15 min (20-25 ml each time in all groups). Group 1: control group (n = 13); group 2: Krebs-Henseleit (K-H) solution with potassium (16 mmol/L) (n = 13); group 3: K-H solution with potassium (16 mmol/L) and pinacidil (50 mumol/L) (n = 13); group 4: K-H solution with potassium (16 mmol/L), pinacidil (50 mumol/L) and glibenclamide (10 mumol/L) (n = 13). The pre-ischemic and post-ischemic myocardial functions were assessed by the percentage recovery of the left ventricular developed pressure (LVDP); the left ventricular end-diastolic pressure (LVEDP); both the positive peak and negative peaks of the first derivative of the left ventricular pressures (+/- dp/dtmax); coronary flow; the level of creatine kinase (CK), lactic dehydrogenase (LDH) and aspartate transcarbamoylase (AST) in coronary sinus venous effluent; and by myocardial ultrastructural changes.

RESULTS:

Before myocardial ischemia, there were no significant differences among the four groups in any of the parameters mentioned above. Post-ischemic recovery of LVDP, LVEDP, +/- dp/dtmax, coronary flow, the level of CK, LDH and AST, and myocardial ultrastructural changes were better in group 3 than those in the three other groups.

CONCLUSIONS:

As a new and effective composition, pinacidil can significantly improve myocardial protection from cardioplegia for immature rabbit hearts.

• Authors: R Lin, X Zhu, Z Zhang, M Kang, Q Xia
• Journal: Chinese medical journal (Chin Med J (Engl)) Vol. 114 Issue 11 Pg. 1184-8 (Nov 2001) ISSN: 0366-6999 [Print] China
• PMID: 11729516 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Potassium Channels
• Pinacidil

Topics

• Animals
• Coronary Circulation
• Diastole (drug effects)
• Female
• Male
• Myocardial Ischemia (physiopathology)
• Myocardial Reperfusion Injury (prevention & control)
• Myocardium (ultrastructure)
• Pinacidil (pharmacology)
• Potassium Channels (drug effects, physiology)
• Rabbits
• Systole (drug effects)