On the subsarcolemmal localization of phenazine ethosulfate-linked alpha-glycerophasphate dehydrogenase activity in pigeon pectoralis white muscle fibres.

In this study frozen sections of avian striated muscles were incubated for mitochondrial alpha-glycerophosphate de hydrognease (alpha=GPD) reaction, and the effect of menadione, phenazine methosulfate (PMS) or phenazine ethosulfate (PES) as intermediate electron acceptors was evaluated. Under histochemical conditions, PMS or PES-linked alpha-GPD reaction was poor in the chicken posterior latissimus dorsi and chicken pectoralis muscles. However, PMS or PES-linked alpha-GPD reaction was present characteristically in the subsarcolemmal mitochondria of the "broad white" fibres of the pigeon pectoralis muscle only; the subsarcolemmal mitochondria of the narrow red fibres lacked such a reaction pattern. The above reaction pattern, however, differed when compared with the menadione-linked alpha-GPD reaction. The present histochemical evidence suggests the existence of an inherent heterogeneity in the mitochondrial populations of the different avian striated muscle fibres studied.