Mouse taste buds were investigated following administration of monoamines and their precursors by fluorescence and electron microscopy. The appearance of fluorescent cells within the taste bud and the ultrastructural changes of vesicles in the gustatory cells were due to the treatment of 5-hydroxytryptophan. Small dense-cored vesicles (30-60 nm in diameter) appeared throughout the cytoplasm and accumulated especially at the presynaptic membranes of afferent synapses. Large dense-cored vesicles (80-100 nm) increased twice in number, and electron densities of their cores became more dense as compared with untreated mice. Fluorescent cells appeared in the taste bud of L-DOPA treated mice, whereas no ultrastructural changes were observed. These results suggest that the gustatory cells of the taste bud are capable of taking up and storing monoamines, which might act as neurotransmitters from the gustatory cells to the nerves.
Summary. After administration of monoamine precursors, taste buds in the fungiform and foliate papillae of the mouse were observed by means of electron microscopy and fluorescence histochemistry.The taste buds in the f ungiform papillae differed in the ultrastructure of their apical regions from those in the foliate papillae, which contained the same taste buds as those described in the circumvallate papillae. The gustatory cells in both the fungiform and foliate papillae were capable of taking up monoamine precursors, although this ability was greater in the latter papillae. The results suggest that, not only in the circumvallate papillae but also in both the foliate and fungiform papillae, monoamines might be involved in neurotransmission from the gustatory cells to the nerves.
Summary.Bone resorption surfaces formed by osteoclasts can be identified as rough areas by scanning electron microscopy (SEM). Iu this study, the endocranial surfaces of mouse parietal bones were examined by SEM at 1, 4, 6, 8,14 and 20 weeks of age in an attempt to understand the bone resorbing activity after the cessation of bone growth.On the inner surface of the parietal bones, the rough areas, composed of a group of 8 to 30 ,um wide concavities, can be divided into two distinct groups (type I and type II). The surface of type I areas appeared irregularly rough and those of type II revealed feather, fire-flame, or wave-like patterns due to characteristic arrangements of the concavities. The rough areas occupying the inner surface of the parietal bones made up about 600 of the surface area at 1 week and about 5% at 4 weeks in both sexes.The rough areas were all type I at this age. After puberty, the rough areas in males occupied about 10% of the inner surface until 20 weeks and consisted of large type I and small type II areas.In females, the proportion of the rough areas increased after puberty and occupied about 40% of the endocranial surface at 14 and 20 weeks.The type I areas were much larger, increasing in size with age and eventually occupying a large proportion of the rough areas. The sex differences in the rough areas were reversed by gonadectomy.The results suggest that male and female gonadal products, possibly sex hormones, have respective inhibitory and stimulatory effects on the formation of bone resorptioe surfaces, and may be responsible for the sex differences in the size and morphological features of the areas on the bone surfaces.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.