Effects of spices on neuropeptide Y (NPY) expression in olfactory nerve cell and human plasma
Date Issued
2009
Date
2009
Author(s)
Wu, Po-Ju
Abstract
Neuropeptide tyrosine (NPY), a 36-amino acid peptide, is widely present in the central and peripheral nervous system, especially abundant in the brain. NPY is the most important stimulator of food intake. On the other hand, essences such as limonene and linalool, which are respectively the major components of grapefruit oil and lavender oil, have been verified to influence (decrease/increase) appetite in rats. Therefore, we propose that appetite regulation effect of spices might be connected with the secretion of NPY. n a previous study, we had established a NPY expression screening model by culturing olfactory nerve cells Rolf B1.T for 2 days and treating cells with limonene and linalool for 10 min. Thus, in this study, we used this model to screen thirteen spices and expected to find potential spices that could stimulate NPY mRNA expression of Rolf B1.T cells. Furthermore, a clinical trial was implemented to study the effects of these spices on the human physiological indicators, including ear temperature, blood pressure, and plasma NPY secretion. Furthermore, leptin is synthesised by adipocytes in proportion to the levels of stored triglycerides, and is a key hormone in the regulation of food intake and energy expenditure. This research also analyzed the leptin content in plasma. In addition, personal’s questionnaire was used to further investigate the relationship between food intake and aroma components. n NPY expression screening model, our result indicated that octenol, pinene, and methyl phenylacetate significantly increased NPY mRNA levels in the Rolf B1.T cells. Moreover, the results of clinical trial were as follows: 1) when the experimental period was 10 min, limonene (negative control) decreased plasma NPY level, indicating that it might inhibit appetite, 2) when the experimental periods were 5, 10 min, linalool (positive control) increased plasma NPY level, indicating that it might stimulate appetite, 3) when the experimental periods were 5, 10 and 15 min, octenol could increase plasma NPY level, revealing that it might be a potent stimulator of food intake, 4) the plasma NPY level in the pinene group had no obviously changes at any experimental time. However, the results of plasma leptin concentrations were inconclusive. We suspected that it was influenced by other physiological factors. Blood pressure and ear temperature were not significantly changed at any experimental time.
Subjects
NPY
olfactory nerve cells
appetite
aromatherapy
human plasma NPY
Type
thesis
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