Effect of Peripheral 5-HT on Glucose and Lipid Metabolism in Wether Sheep

In mice, peripheral 5-HT induces an increase in the plasma concentrations of glucose, insulin and bile acids, and a decrease in plasma triglyceride, NEFA and cholesterol concentrations. However, given the unique characteristics of the metabolism of ruminants relative to monogastric animals, the physiological role of peripheral 5-HT on glucose and lipid metabolism in sheep remains to be established. Therefore, in this study, we investigated the effect of 5-HT on the circulating concentrations of metabolites and insulin using five 5-HT receptor (5HTR) antagonists in sheep. After fasting for 24 h, sheep were intravenously injected with 5-HT, following which-, plasma glucose, insulin, triglyceride and NEFA concentrations were significantly elevated. In contrast, 5-HT did not affect the plasma cholesterol concentration, and it induced a decrease in bile acid concentrations. Increases in plasma glucose and insulin concentrations induced by 5-HT were attenuated by pre-treatment with Methysergide, a 5HTR 1, 2 and 7 antagonist. Additionally, decreased plasma bile acid concentrations induced by 5-HT were blocked by pre-treatment with Ketanserin, a 5HTR 2A antagonist. However, none of the 5HTR antagonists inhibited the increase in plasma triglyceride and NEFA levels induced by 5-HT. On the other hand, mRNA expressions of 5HTR1D and 1E were observed in the liver, pancreas and skeletal muscle. These results suggest that there are a number of differences in the physiological functions of peripheral 5-HT with respect to lipid metabolism between mice and sheep, though its effect on glucose metabolism appears to be similar between these species

Seasonal change of nitrogen cycling in Hichirippu lagoon: Get tough for sustainable use of the coastal area.

Hichirippu lagoon is inhabited by many animals and benthic plants (e.g. Japanese red-crowned crane, swan and seagrass), and is designated as a wetland under the Ramsar Convention. We quantified the nitrogen cycling in Hichirippu lagoon with a focus on food web and mass balance. The fishery yield (bivalves) in this lagoon is estimated at 25 ton/km'/yr, as high as that of the Seto Inland Sea. The aim of this study was to determine the major biological process supporting the high bird's population and fishery yield. We conclude that (1) the mass balance of Hichirippu lagoon is perfect for sustainable use, (2) it is informative to understand ecosystem of Hichirippu lagoon for all who have the same goal as sustainable society. Consequently, we point out that researchers will have to pay attention to not only what happens in polluted area, but also to what we can learn from unpolluted ecosystem

Autofluorescent bodies in the toxic dinoflagellate Alexandrium tamarense: A potential indicator of the physiological condition of the species

Autofluorescent bodies were examined in cultured and natural cells of Alexandrium tamarense (Lebour) Balech collected from Ofunato Bay, Japan. Three different autofluorescent bodies (pale blue, light blue, and white) and the autofluoresced chloroplast were observed under ultraviolet light excitation. We suggest that the pale-blue and light-blue bodies represent a novel type in dinoflagellates based on their fluorescent properties. We also found that cells with pale-blue and light-blue bodies appeared predominantly in the early and middle to late exponential phases, respectively. A similar pattern was observed in natural populations during a 2-year field survey. Cells with pale-blue bodies were dominant almost one week before the bloom, whereas those with light-blue bodies were mostly apparent during the blooming stage. These results indicate that the observation of autofluorescent bodies could be useful as a physiological indicator for predicting natural population blooms of A. tamarense in Ofunato Bay

Gender-specific impacts of apnea, age, and BMI on parasympathetic nerve dysfunction during sleep in patients with obstructive sleep apnea.

BACKGROUND: The gender-specific influences of various confounding factors, including apnea, age, BMI, and cigarette consumption, on the function of the parasympathetic nerve system (PNS) during sleep in OSA patients has never been investigated. METHODS: One hundred ninety-seven males and 63 females with OSA were subjected to full PSG examinations including assessment of R-R intervals (RRIs) during an overnight ECG. The PNS-derived modulatory effect on the RRIs and the variability of this effect were quantified during REM and NREM using instantaneous time-frequency analysis with complex demodulation. The spectral domain with the maximum instantaneous amplitude in the high-frequency band between 0.15 and 0.4 Hz was defined as the main HF peak and used as a surrogate marker of PNS discharge. Based on density-spectrum-array maps of the main HF peaks (HF-DSA map), shifts in the central frequency of the main HF peak over time were continuously observed. When the main HF peaks on the HF-DSA maps maintained the same central frequency for more than 20 sec or 5 min, the PNS functions were considered to be "stable" or "very stable", respectively. RESULTS: Apneas enhanced PNS-derived cardiac-modulation during REM in males, but more importantly, they made PNS-function unstable during both REM and NREM in males and during NREM in females. Aging blunted the PNS-derived cardiac-modulation during both REM and NREM regardless of gender, but aging had no impact on the stability of PNS-function. BMI blunted PNS-eliciting cardiac-modulation during REM in males and during NREM in both males and females. BMI made the PNS unstable during REM in females. Neither height nor cigarette consumption influenced any PNS-related parameter. CONCLUSIONS: The PNS-derived cardiac-modulation was generally inhibited by aging and obesity, in which the effect of obesity was gender-specific. The PNS instability at nighttime was mainly induced by apneas but by obesity particularly during REM in females