Effect of propranolol on accumulation of NEFA in the ischemic perfused rat heart.

The effect of propranolol on the accumulation of non-esterified fatty acids (NEFA) in the isolated, perfused working rat heart was investigated. Ischemia was induced by lowering the afterload pressure to 0 mm Hg for 20 min and for reperfusion, the pressure was raised to the pre-ischemic pressure (60 mm Hg) for 20 min. The heart was frozen for biochemical studies immediately after ischemia or reperfusion. Ischemia decreased mechanical function, increased the levels of palmitoleic, arachidonic and linoleic acids, left oleic, lauric, myristic, palmitic and stearic acids unchanged, decreased the levels of adenosine triphosphate (ATP), creatine phosphate (CrP) and the energy charge potential (ECP), and increased the level of lactate. Propranolol (10(-5) or 3 x 10(-5) M) restored mechanical function and inhibited the changes in NEFA, ATP and ECP caused by ischemia. It is suggested that propranolol inhibits the decrease in mechanical function and high energy phosphates caused by ischemia, and thereby inhibits the accumulation of NEFA, especially of the unsaturated fatty acids such as arachidonic acid, during ischemia.