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Biomedical subjects

J R Garrett

Publications and source records attributed to J R Garrett.

At least 163 records · Page 9Linked to original sources
PubMed1976

Secretory and structural effects of 6-hydroxy-dopamine on normal parotid glands of rats, and at different times after surgical sympathectomy.

The effects of i.v. 6-hydroxydopamine (6-OHDA), 100 mg/kg, have been studied on parotid glands of rats at 12, 24, 48, 72 hr and 3 weeks after avulsion of the right superior cervical sympathetic ganglion. The salivary flow from normal left control glands and from right glands 12 hr after ganglionectomy were similar, but at longer times after ganglionectomy the secretory response from the test glands was greatly reduced. Morphological assessment showed that 6-OHDA induced a massive depletion of secretory granules from all control glands and also at 12 hr after ganglionectomy but at 48 and 72 hr there was considerably less depletion of granules on the ganglionectomized side. It is thought that at the longer times after ganglionectomy the secretion from the test glands is caused by circulating catecholamines released by the action of 6-OHDS on adrenergic nerves elsewhere, plus a possible small direct secretogogue effect oomy are thought to be attributable to the release of catecholamines from adrenergic nerves within the gland.

Animals↗
PubMed1976

Myoepithelial activity and the appearances of sialograms: a possible role in the formation of sialectasis.

In experimental studies on dogs it has been shown that the sialographic filling of the ductal system may be severely restricted if the myoepithelial cells are contracting and it seems likely that myoepithelial activity in man will also influence sialographic appearances. It has also been found that when secretory forces were accompanied by myoepithelial contraction against a sialographic pressure the ersuing damage to striated ducts produced appearances of sialectasis. IT IS WONDERED WHETHER SIMILAR EVENTS MAY SOMETIMES BE RESPONSIBLE FOR SIALECTATIC APPEARANCES IN MAN.

Animals↗
PubMed1975

Structural changes associated with parotid "degeneration secretion" after post-ganglionic sympathectomy in rats.

Parotid glands of rat have been examined 12, 24 and 48 hours after avulsion of the cervical sympathetic ganglion and compared with normally innervated left glands. Formaldehyde-induced fluorescence showed a relatively normal complement of adrenergic nerves at 12 hours but most of the nerves had lost their noradrenaline content by 24 hours and no fluorescent nerves were detected at 48 hours. Ultrastructural degenerative changes in axons were rare at 12 hours, common at 24 hours, and the degenerating axons appeared to have disappeared by 48 hours. The glands looked whitish and pale and similar to the controls at 12 and 48 hours but were pinkish and oedematous on the sympathectomised side at 24 hours. Correspondingly the acini were loaded with secretory granules at 12 and 48 hours but were extensively depleted of granules at 24 hours. This loss of granules is considered to be due to sympathetic "degeneration secretion" caused by the release of noradrenaline from the degenerating adrenergic nerves between 12 and 24 hours after ganglionectomy. This is thought to be the first example of morphological change resulting from "degeneration activation" to be recorded microscopically.

Animals↗
PubMed1975

Effects of nerve stimulation and denervation on secretory material in submandibular striated duct cells of cats, and the possible role of these cells in the secretion of salivary kallikrein.

Striated ducts in cats after 24 hours starvation normally contained glycogen, especially in the basal regions. They also contained neutral mucin and tryptophan in apical parts of "light" cells and small irregular "secretory" granules were found in a similar distribution by electron microscopy.--Parasympathetic nerve stimulation caused a loss of glycogen but no apparent change in the apical secretory material, despite a copious secretion.--Sympathetic stimulation caused a loss of glycogen and an extensive depletion of apical secretory material, although the salivary flow was small.--Parasympathetic denervation caused progressive atrophy of striated ducts and oedematous degeneration of some cells occurred. Persisting "light" cells tended to contain few basal infoldings, few mitochondria and little apical secretory material.--Sympathetic denervation caused a loss of apical secretory material between 2-4 days, which may have been due to "degeneration activation". Thereafter little change was evident but some ductal atrophy had occurred by 32 days.--These changes in ductal secretory material correspond more closely than acinar changes to the alterations in glandular and salivary kallikrein resulting from similar experiments by other workers. It therefore seems likely that submandibular salivary kallikrein in the cat is present in the secretory material of striated ducts.

Animals↗
PubMed1975

Changes in parotid acinar cells accompanying salivary secretion in rats on sympathetic or parasympathetic nerve stimulation.

Morphological and secretory effects of stimulating autonomic nerves have been studied in parotid glands of rats. Sympathetic stimulation evoked a slow flow of saliva which had a high concentration of amylase. After long term sympathetic stimulation secretory granules were heavily depleted from the parotid acinar cells. Parasympathetic stimulation evoked a copious flow of saliva with a low concentration of amylase. However, at high frequency stimulation the total amount of amylase secreted on parasympathetic stimulation was as great or even greater than on symphatetic stimulation, nevertheless, any loss of secretory granules from the acinar cells was very small. It is concluded that secretion of parotid acinar granules in the rat is prinicipally a sympathetic function. Secretion of fluid is more effectively produced by parasympathetic stimulation and much of the amylase in such saliva appears to have arisen from sources other than the secretory granules.

Amylases↗
PubMed1975

Experimental salivary mucoceles in cat. A histochemical study.

Ductal ligation of the sublingual gland induced mucocele formation in a high percentage of cats. Extravasated mucus was associated with all sublingual glands up to 20 days after ligation, and extravasation mucoceles were associated with 12 out of 27 sublingual glands between 7 and 365 days after ligation. Enzyme-histochemic examination revealed that the extravasated mucus induced a migration of macrophages and a fibroblastic reaction. It is thought that if these reactions are sufficiently intense in the early days after ligation, then continued spread of extravasated mucus and mucocele formation does not occur; however, if the extravasation is too great to be contained, a mucocele forms in which a balance develops between extravasation of mucus and its removal. Possibly the numerous macrophages in the mucoceles are involved in degrading mucus and facilitating its removal.

Acid Phosphatase↗