Figure 1.

Skeletal muscle cells from euthermic (a, c) and hibernating (b, d-f) edible dormice; Epon-embedded samples, uranyl acetate and lead citrate staining. During hibernation, myofibres do not show evident structural modifications at both the light (a, b) and electron microscopic level (c, d) apart from the presence of some lipid droplets (L) (d), which are frequently surrounded by mitochondria (M) (e). Myonuclei also display their usual morphology with elongated shapes, finely irregular borders, condensed chromatin clumps (C) distributed both at the nuclear and nucleolar periphery, and one roundish nucleolus (Nu). Bars = a, b: 20 μm; c-f: 0.5 μm.