title: [An electron microscope study of the inner circular layer and related interstitial Cajal cells of the small intestine of the hedgehog (Erinaceus europaeus) during its annual cycle].
abstract: The inner portion of the circular layer (the special layer) of the small intestine of the hedgehog (Erinaceus europaeus) and its related interstitial cells of Cajal (ICC) were studied by electron microscopy for the first time in the literature. Hedgehogs were studied in active conditions, during hibernation and at arousal. The structure of the inner portion of the circular layer of the hedgehog is similar to that observed in other mammals a special layer formed by thin muscle cells may be recognized; a plexus muscularis profundus (PMP) and ICC are localized between this layer and the outer portion of the circular layer; the PMP is rich in varicosities with many synaptic vesicles (both small agranular and large granular vesicles); most varicosities are in close contact with the ICC; the ICC are closely resembling those described for man, since they have several cytological features very similar to those of smooth muscle cells. During hibernation glycogen particles and caveolae are very numerous and the Golgi apparatus is poorly developed both in the ICC and in the smooth muscle cells of the special layer; in the PMP the synaptic vesicles, especially the large granular ones, are greatly reduced in number. At the beginning of arousal the glycogen particles disappear; at the end of arousal the caveolae are as numerous and the Golgi apparatus as large as in the active conditions both in ICC and in smooth muscle cells. The synaptic vesicles, following the gradual increase of body temperature, become numerous and at the end of arousal their number is similar to or greater than in active conditions.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D001831:Body Temperature; D006003:Glycogen / Q000032:analysis; D006364:Hedgehogs / Q000033:anatomy & histology*; D006605:Hibernation; D007421:Intestine, Small / Q000166:cytology*; D008854:Microscopy, Electron; D012621:Seasons; D013572:Synaptic Vesicles / Q000648:ultrastructure
chemical_list: D006003:Glycogen
vernacular_title: Studio al M.E. della porzione interna dello strato circolare e delle relative cellule interstiziali del Cajal del tenue del riccio (Erinaceus europaeus) durante il ciclo annuale.