Nuclear bodies are usual constituents in tissues of hibernating dormice

In previous studies we demonstrated in several tissues of the hazel dormous e Muscardinus avellanarius that during hibernation cell nuclei contain part icular structural constituents absent in euthermia. In the present study we examine the same tissues in euthermic and hibernating individuals of the e dible dormouse Glis glis in order to investigate possible modifications of nuclear structural constituents occurring during hibernation in this specie s. Edible dormice were captured in the wild and maintained in an external anim al house. Samples of liver, pancreas, brown adipose tissue and adrenal cort ex were taken from three hibernating and three euthermic animals and proces sed for resin embedding. Ultrastructural and immunocytochemical studies wer e carried out on cell nuclei of these tissues. The most evident feature of cell nuclei of hibernating dormice was the pres ence of several nuclear bodies, namely fibro-granular material, amorphous b odies, coiled bodies, perichromatin granule-like granules and nucleoplasmic fibrils, the distribution of which was peculiar to each tissue. No one of these constituents was detectable during euthermia. Immunocytochemical anal yses revealed that they contain some splicing factors. Apart from some differences, maybe due to the different characteristics of lethargy, the nuclear bodies found in edible dormice were morphologically a nd immunocytochemically similar to those previously described in the same t issues of hazel dormice. They therefore seem to be strictly correlated to t he hibernating state. If they represent storage and/or assembly sites of sp licing factors to be rapidly used upon arousal, they could represent a usua l structural feature in cells of hibernating species. Anat Rec 254:389-395, 1999. (C) 1999 Wiley-Liss, Inc.