Objective: Purinergic receptors have been localized in several tissues and proposed to be involved in various signalling pathways, including that of glucose uptake by inducing translocation of glut-4 vesicles to the cell membrane. We have found the P2X1 receptor to be localized in skeletal muscle cells (Thaning et al, Diabetes 2009), supporting a role for these receptors in skeletal muscle metabolism. The objective of the present study was to determine the distribution of purinergic receptors in skeletal muscle cells and to quantify the expression in healthy versus diabetic subjects. Methods: Muscle biopsies from vastus lateralis were obtained from four type 2 diabetic patients and four age-matched healthy controls. Antibodies against P2Y1, 2, 4, 11, 12 and P2X1, 4 receptors were tested immunohistochemically with confocal microscopy on transverse sections of a muscle biopsy. The receptors P2X1, P2Y4 and P2Y11 were found to be visible in the muscle cells and were thus selected for further morphological analysis by confocal microscopy (TCS SP2 system). Results: P2Y11 receptors were diffusely but clearly expressed intracellularly, especially in type 1 fibres but they were also found in type II fibres. P2X1 receptors were expressed in intracellular vesicles. P2Y4 receptors were visible in low amounts in the skeletal muscle sarcolemma. P2X1 and P2Y4 showed no fiber-type differences. Expression levels is not yet fully quantified, therefore it has not been possible to compare healthy versus diabetic subjects, however results will be presented at the conference Conclusion: The current study demonstrates for the first time that purinergic receptors P2X1 and P2Y11 are located intracellularly in human skeletal muscle fibres. We speculate, that this intracellular localization reflects a role for purinergic receptors in the regulation of skeletal muscle metabolism, potentially of glucose uptake. Further functional investigations are required to confirm this hypothesis.