<原著>冬眠動物における頚動脈小体の季節変化について

概要

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The carotid body as an arterial chemosensory organ regulates respiration, and its parenchymal cellscontain several neuropeptides. Therefore, it would be of interest to identify differences in thephysiological state and the distribution of several neuropeptides between hibernating and nonhibernatinganimals. We examined immunohistochemically the distribution of several neuropeptides inthe carotid bodies of two mammalian species to study the role of the organ in the hibernation,focusing on differences in the vital signs between the hibernation and nonhibernation periods.Hibernation represents a physiological adaptation to the severe environment during winter. Vitalsigns such as respiration rate, heart rate and body temperature in hibernating animals are markedlydecreased and the depression and heart rate in particular could result in hypoxia.Respiration rate and heart rate during hibernation were less than one tenth of those during nonhibernation.Intense immunoreactivities for tyrosine hydroxylase(TH) and glutamate(Glu) was observed as smallgroups in the glomus cells of the carotid body during the non-hibernation phase. In the hibenatinganimals, mild. methionin-enkephaline(Met-Enk) immunoreactivities were evident in almost all glomuscells and some nerve fibers.In the electron microscopic observation,the visible difference of the size and morphology observedthe mitochondoria in glomus cells of the both animals.