Possible involvement of melatonin in tooth development: expression of melatonin 1a receptor in human and mouse tooth germs

Self Cite

Melatonin, discovered in 1958, is secreted by the pineal gland primarily during the night. Its secretion is controlled by the light/dark cycle of the environment. Melatonin is also produced in and secreted by various extrapineal organs, tissues and cells and its synthesizing enzyme arylalkylamine N-acetyltransferase (AANAT) is expressed in various extrapineal organs, tissues and cells. Recently, it was reported that melatonin is present in saliva, but it is not certain where melatonin was synthesized and whether it was secreted into saliva and what function it may have in saliva. The present study was performed to investigate where melatonin was synthesized and whether it was secreted by salivary glands into saliva. We performed immunohistochemical analysis of the expression of AANAT in rat parotid, submandibular and sublingual glands and the expression of both AANAT and hydroxyindole-O-methyltransferase (HIOMT) in human submandibular glands. We evaluated the expression of AANAT and HIOMT mRNA in rat submandibular glands by quantitative reverse transcription-polymerase chain reaction. As a result, we observed expression of AANAT in epithelial cells of striated ducts in rat salivary glands and expression of AANAT, HIOMT and melatonin in epithelial cells of striated ducts in human submandibular glands. In addition, we also confirmed the expression of the most potent melatonin receptor, melatonin 1a receptor, in rat buccal mucosa. Our findings suggest that melatonin might be produced and secreted by salivary glands directly into saliva and that it might play some physiological role in the oral cavity.

Section: Introductionmentioning

confidence: 99%

Expression and cellular localizaion of melatonin-synthesizing enzymes in rat and human salivary glands

Shimozuma

Tokuyama

Tatehara

et al. 2011

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“…Concurrent with these events, inner enamel epithelial cells differentiate into ameloblasts and secrete the enamel matrix. In the process of matrix formation, ameloblasts and odontoblasts are considered to be regulated not only by local growth factors, but also by systemic hormones such as growth hormone and melatonin (Kumasaka et al 2010). Moreover, for sufficient matrix proteins to be made, it seems to be critical for ameloblasts and odontoblasts to be supplied with rich nutritious materials.…”

Section: Discussionmentioning

confidence: 99%

Leptin and vascular endothelial growth factor regulate angiogenesis in tooth germs

Ide

Tokuyama

Davaadorj

et al. 2011

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Leptin, a 16 kDa non-glycolated polypeptide of 146 amino acids produced by the ob gene, has a variety of physiological roles not only in lipid metabolism, hematopoiesis, thermogenesis and ovarian function, but also in angiogenesis. This study focuses to investigate the possibility that leptin, as an angiogenic factor, may regulate the angiogenesis during tooth development. We firstly studied the expression of leptin and vascular endothelial growth factor (VEGF) during tooth development immunohistochemically. This investigation revealed that leptin is expressed in ameloblasts, odontoblasts, dental papilla cells and stratum intermedium cells. This expression pattern was similar to that of VEGF, one of the most potent angiogenic factors. Interestingly, more leptin-positive cells were observed in the upper third portion of dental papilla, which is closest to odontoblastic layer, compared to middle and lower thirds. Moreover, in the dental papilla, more CD31 and/or CD34-positive vascular endothelial cells were observed in the vicinity of ameloblasts and odontoblasts expressing leptin and VEGF. These findings strongly suggest that ameloblasts, odontoblasts and dental papilla cells induce the angiogenesis in tooth germs by secretion of leptin as well as VEGF.

“…(Nakade et al 1999;Roth et al 1999)] encouraged Kumasaka et al (2010) to investigate involvement of melatonin in tooth development and growth by immunolocalization of Mel1aR, the most potent transmembrane receptor for melatonin, using tooth germs from humans (late bell stage) and neonatal mice. They found Mel1aR to be expressed in secretory ameloblasts, the cells of the stratum intermedium and stellate reticulum, external dental epithelial cells, odontoblasts and dental sac cells.…”

Section: Moleculesmentioning

confidence: 99%

Histochemistry and cell biology: the annual review 2010

Hübner

Efthymiadis

2011

This review summarizes recent advances in histochemistry and cell biology which complement and extend our knowledge regarding various aspects of protein functions, cell and tissue biology, employing appropriate in vivo model systems in conjunction with established and novel approaches. In this context several non-expected results and discoveries were obtained which paved the way of research into new directions. Once the reader embarks on reading this review, it quickly becomes quite obvious that the studies contribute not only to a better understanding of fundamental biological processes but also provide use-oriented aspects that can be derived therefrom.