EFFECTS OF ISCHEMIA ON TISSUE METABOLITES IN RED (SLOW) AND WHITE (FAST) SKELETAL-MUSCLE OF THE CHICKEN

Brief periods of ischemia have been shown to produce marked reactive hyperemia in both red (slow) and white (fast) skeletal muscle. However, evidence is lacking for specific vasodilator metabolites which are rapidly produced in ischemic skeletal muscle. The present study examined the effects of 1 and 3 minutes of ischemia on creatine phosphate (CrP), adenine nucleotide metabolism, and anaerobic glycolysis in red anterior (ALD) and white posterior latissimus dorsi (PLD) muscles of the chicken. Tissue metabolite concentrations were determined from perchloric acid or trichloroacetic acid extracts using enzymatic assay or high pressure liquid chromatography. CrP or adenine nucleotides were not significantly altered in either muscle following 1 or 3 minutes of ischemia. However, adenosine increased by 611% in the ALD at 1 minute. Following 3 minutes of ischemia, adenosine concentrations were elevated by 439% and 201% in the ALD and PLD, respectively. The PLD showed the greatest increases in inosine and IMP. Inorganic phosphate increased by 67% and lactate increased by 142% in the ALD at 3 minutes. The PLD, which is reported to have a high anaerobic glycolytic capacity, showed no increase in lactate. These results support the hypothesis that adenosine may be a mediator of skeletal muscle reactive hyperemia following short periods of ischemia.