Purification of inorganic pyrophosphatase from rat salivary glands

Inorganic pyrophosphatase [EC 3.6.1.1] isolated from rat sublingual and submandibular glands was purified 2300-fold and 2600-fold, respectively. The purified enzymatic preparations separated on electrophoresis into two protein bands, of which only one showed the pyrophosphatase activity. Inorganic pyrophosphatase from rat salivary glands is a monomeric anionic protein, its isoelectric point is 5.42 and 4.90 for the sublingual and submandibular glands, respectively.     

Subcellular localization of inorganic pyrophosphatase in rat salivary glands

Inorganic pyrophosphatase (EC 3.6.1.1) from cells of the sublingual and submandibular salivary glands of rat was found only in the cytosol and was absent in nuclei, mitochondria, lysosomes and microsomes.     

Dependence of Balbiani ring induction in Chironomus salivary glands on inorganic phosphate

Galactose or certain other monosaccharides, administered for several days in the culture medium to larvae of Chironomus pallidivittatus, induce a new Balbiani ring, BR6, in their salivary gland chromosomes (W. Beermann, 1973, Chromosoma, 7, 198–259). This also applies to ethanol (Beermann, personal communication) and as found here, to glycerol. Induction of BR6 has previously been found to be paralleled by the appearance of one or two giant proteins (Ic₁ and Ic₂) probably deriving from allelic genes. We record here that the induction also includes the production of a new giant RNA species similar in size to the RNA from the Balbiani rings normally present, BR1 and BR2. Administration of inorganic phosphate together with glycerol prevented the appearance of BR6, as well as of the new RNA and component Ic protein(s); by contrast chloride and sulfate at similar concentrations did not prevent these effects. Administration of inorganic phosphate several days after the inducer and its continued presence reversed the effect of induction. Glycerol caused a marked depression in the level of inorganic phosphate in the hemolymph which persisted throughout its administration; the phosphate level in the glands was, however, unaffected. Inorganic phosphate administered together with the inducer at equimolar concentrations largely prevented the decrease in phosphate levels. It is concluded that a decrease in phosphate level is required for BR6 induction by glycerol. The two other inducers, galactose and ethanol, which were studied in less detail, seem to have a similar action.     

Ultrastructure of Human labial salivary glands

Summary Human labial salivary glands, obtained by biopsy from 32 subjects, were studied by light and electron microscopy. Intranuclear inclusions, unrelated to nucleoli, were present in many of the acinar nuclei in glands from 16 of the 32 donors. More than one inclusion was sometimes observed within a single nucleus. They measured about 1 in diameter, and were stainable in a variety of ways. They were eosinophilic, some were stained by Nile blue sulphate, some were PAS-positive, and all were Feulgen-negative. They were bounded by a single membrane, which never exhibited continuity with the nuclear envelope, and they showed considerable morphological variation. The more complex inclusions consisted of alternating shells of light and dark material with tiny dense granules embedded in the latter. The intranuclear inclusions, which apparently were non-viral in origin, were in some way related to the secretory cycle of the mucous cells, since they were found only in immature cells, and never in cells in which secretory products were abundant.This work was supported in part by grants from the Henry Spenadel Trust and the Max C. Fleischmann Foundation of Nevada, by grant CA-08748 from the National Cancer Institute, by grant 5 SO1 FR 05335-07 from the National Institutes of Health, by a grant from the National Cystic Fibrosis Research Foundation, and by an Institutional Grant to the School of Dental and Oral Surgery, Columbia University, from the National Institutes of Health.The authors are indebted to Dr.Louis Mandel for performing the biopsies used in this study. The expert technical assistance of Mrs.Mona Seggio is acknowledged.     

The innervation of locust salivary glands

Summary The salivary glands of the locustSchistocerca gregaria are influenced by at least two nerves. The suboesophageal salivary nerve (nerve 7b) is excitatory eliciting copious secretion when active. The prothoracic posterior transverse nerve is also capable of evoking increases in secretion, but only if the innervation from the salivary nerve is present. This is, in part, because activity in the transverse nerve influences the firing of the two suboesophageal salivary neurones that have their axons in the salivary nerve. The effect of the salivary nerve is mimicked by both 5-HT and dopamine, whereas the action of the transverse nerve on the glands is mimicked by the peptides YGGFMRFamide and YGGFLRFamide.Abbreviations 5-HT 5-hydroxytryptamine - cAMP cyclic adenosine monophosphate - SN salivary neurone - HPLC high performance liquid chromatography     

Nervous control of mammalian salivary glands

In the production and flow of saliva, sympathetic and parasympathetic nerves generally cooperate, although variations between the different salivary glands are considerable, particularly in the sympathetic innervation. In the submandibular gland of the dog, sympathetic impulses cause secretion via beta-adrenoceptors, and since sympathetic motor effects are elicited via alpha-adrenoceptors it is possible to study separately motor and secretory effects in this gland. Such experiments indicate that myoepithelial contractions serve to accelerate the salivary flow and to support the secreting acinar cells and prevent back-flow of fluid from the luminal system into the glandular tissues. The contractions are elicited reflexly from the oral mucosa together with secretion. A potentiation interaction between sympathetic and parasympathetic nerves occurs in the formation of the primary saliva. In parotid glands of rabbits and rats such an interaction has been demonstrated in the secretion of amylase.