• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.447-463
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• 2001

Dendroaspis natriuretic peptide (DNP), a fourth member of the natriuretic peptide isolated from the venom of the Dendroaspis angusticeps snake, has been reported to be present in human plasma and atrial myocardium and caused vasorelaxation and diuresis in experimental animals. However, it is uncertain whether they are present in peripheral organs other than the heart and its further physiological roles also remains to be clarified. To assess the possible physiological role of DNP in the salivary glands, I investigated the localization of DNP peptide in the rat salivary glands by immunohistochemistry and the binding sites for radiolabelled DNP in the rat salivary glands and oral mucosa using in vitro autoradiography. DNP immunoreactivity was widely distributed in the submandibular, sublingual and parotid glands, particularly in the ducts such as the intercalated and striated ducts, where atrial natriuretic peptide (ANP) was colocalized in consecutive sections, but not in acini. High density $^{125}I-DNP$ binding sites were localized in the epithelia of the tongue and hard palate, while low density binding sites for $^{125}I-DNP$ were also distributed in the submandibular, sublingual, and parotid glands. In the hard palate and tongue, the precise location of this binding was revealed on the basal and parabasal cells of the epithelia by emulsion microautoradiography. These results suggest that DNP may not only have a role in the salivary glands but also play a role in the regulation of growth in the oral epithelium, particularly in the hard palate and tongue.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.72-81
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• 2001

Dendroaspis natriuretic peptide (DNP), recently isolated from the venom of the green Mamba snake Dendroaspis angusticeps, is a 38-amino acid peptide containing a 17-amino acid disulfide ring structure similar to that of the natriuretic peptide family. The natriuretic peptide family was known to induce histamine release from human and rat mast cells, but there are no published data concerning the effects of DNP on histamine release from mast cells. The purpose of this study is to investigate whether DNP induces the histamine release from rat peritoneal mast cells (RMPCs) and to determine the mechanism of DNP-induced histamine release from RPMCs. After treatment of the various doses of DNP in RPMCs, the mast cell degranulation was observed with inverted microscopy and the histamine release was measured by radio-enzymatic assay. Calcium uptake and intracellular cyclic GMP level were measured by radioimmunoassays. DNP induced the mast cell degranulation. DNP released the histamine and increased the calcium uptake and the level of intracellular cyclic GMP of RPMCs, in a dose-dependent manner. The results indicate that DNP is capable of inducing histamine release from RPMCs by increasing of calcium uptake and intracellular cyclic GMP level.