RESUMO
5-Hydroxytryptamine (5-HT) and its receptor have been localized and quantified in the submaxillary gland of rats of various ages, using immunohistochemistry, in situ hybridization and in situ quantification. In male rats, the epithelial cells of serous acini, intercalated ducts, secretary tubes and excretory ducts all showed 5-HT and 5-HT receptor (5-HTR) immunoreactivity. Both 5-HT and 5-HTR reactive sites were found in the same cells of adjacent sections. 5-HT1A receptor mRNA hybridized signals could be detected in cytoplasm of these cells. The parasympathetic ganglia cells and endothelial cells of small vessels also showed 5-HT and 5-HTR immunoreactivity in the cytoplasm. However, in female rats, only the epithelial cells in excretory tubes showed 5-HT and 5-HTR immunoreactivity. The immunoreactivity was present in the same cells of adjacent sections. The relative content of 5-HT and its receptor increased during the first 60 postnatal days but remained constant from day 60 to day 90 postnatum. These results suggest that the submaxillary gland of rats possess autocrine 5-HT, which may regulate the function and development of the gland.
Assuntos
Receptor 5-HT1A de Serotonina/análise , Serotonina/análise , Glândula Submandibular/química , Envelhecimento/metabolismo , Animais , Feminino , Imuno-Histoquímica , Hibridização In Situ , Masculino , RNA Mensageiro/análise , RNA Mensageiro/metabolismo , Ratos , Ratos Sprague-Dawley , Receptor 5-HT1A de Serotonina/metabolismo , Serotonina/metabolismo , Glândula Submandibular/imunologia , Distribuição Tecidual/imunologiaRESUMO
Understanding the molecular composition is of great interest for both nacre formation mechanism and biomineralization in mollusk shell. A cDNA clone encoding an MSI31 relative, termed MSI7 because of its estimated molecular mass of 7.3 kDa, was isolated from the pearl oyster, Pinctada fucata. This novel protein shares similarity with MSI31, a prismatic framework protein of P. fucata. It is peculiar that MSI7 is much shorter in size, harboring only the Gly-rich sequence that has been proposed to be critical for Ca(2+) binding. In situ hybridization result showed that MSI7 mRNA was expressed specifically at the folds and outer epithelia of the mantle, indicating that MSI7 participates in the framework formation of both the nacreous layer and prismatic layer. In vitro experiment on the function of MSI7 suggested that it accelerates the nucleation and precipitation of CaCO(3). Taken together, we have identified a novel matrix protein of the pearl oyster, which may play an important role in determining the texture of nacre.
Assuntos
Calcificação Fisiológica , Carbonato de Cálcio/metabolismo , Ostreidae/metabolismo , Proteínas/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Carbonato de Cálcio/química , Precipitação Química , Clonagem Molecular , Cristalização , DNA Complementar/genética , Dados de Sequência Molecular , Ostreidae/química , Ostreidae/genética , Estrutura Secundária de Proteína , Proteínas/química , Proteínas/genética , Proteínas/isolamento & purificação , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Alinhamento de SequênciaRESUMO
We investigated the rat submaxillary gland for the presence of GnRH and GnRH receptors, the localization and colocalization of GnRH, GnRH receptor and their mRNA, and studied the sequence of GnRH receptor complementary DNA (cDNA) by immunohistochemistry, in situ hybridization and RT-PCR. The results showed that GnRH and GnRH receptor immunoreactive materials were colocalized in the epithelial cells of the serous acinus and glandular duct. The GnRH and GnRH receptor mRNA hybridization signals were detected in the above cells. The sequence obtained from the RT-PCR product was identical to the published cDNA sequence of GnRH receptor in the rat pituitary. The results suggested that the rat submaxillary gland was capable of synthesizing GnRH and GnRH receptors. GnRH may be involved in the functional regulation of the submaxillary gland through autocrine or paracrine activity.
