Methamphetamine induces a rapid increase of intracellular Ca(++) levels in neurons overexpressing GCaMP5.

In this study, methamphetamine (Meth)- and glutamate (Glu)-mediated intracellular Ca(++) (Ca(++) i) signals were examined in real time in primary cortical neurons overexpressing an intracellular Ca(++) probe, GCaMP5, by adeno-associated viral (AAV) serotype 1. Binding of Ca(++) to GCaMP increased green fluorescence intensity in cells. Both Meth and Glu induced a rapid increase in Ca(++) i, which was blocked by MK801, suggesting that Meth enhanced Ca(++) i through Glu receptor in neurons. The Meth-mediated Ca(++) signal was also blocked by Mg(++) , low Ca(++) or the L-type Ca(++) channel inhibitor nifedipine. The ryanodine receptor inhibitor dantrolene did not alter the initial Ca(++) influx but partially reduced the peak of Ca(++) i. These data suggest that Meth enhanced Ca(++) influx through membrane Ca(++) channels, which then triggered the release of Ca(++) from the endoplasmic reticulum in the cytosol. AAV-GCaMP5 was also injected to the parietal cortex of adult rats. Administration of Meth enhanced fluorescence in the ipsilateral cortex. Using immunohistochemistry, Meth-induced green fluorescence was found in the NeuN-containing cells in the cortex, suggesting that Meth increased Ca(++) in neurons in vivo. In conclusion, we have used in vitro and in vivo techniques to demonstrate a rapid increase of Ca(++) i by Meth in cortical neurons through overexpression of GCaMP5. As Meth induces behavioral responses and neurotoxicity through Ca(++) i, modulation of Ca(++) i may be useful to reduce Meth-related reactions.

Mulberry extract inhibits oleic acid-induced lipid accumulation via reduction of lipogenesis and promotion of hepatic lipid clearance.

BACKGROUND: Mulberries are a traditional edible food used to treat hepatic disease. The anti-obesity and hypolipidemic effects of mulberry water extracts (MWE) have attracted increasing interest. In the present study, MWE were assessed for their hepatic lipid-lowering potential when administered in fatty acid overload conditions in HepG2 cells. RESULTS: We found that MWE significantly reduced lipid accumulation, suppressed fatty acid synthesis, and stimulated fatty acid oxidation. Furthermore, MWE also inhibited acetyl coenzyme A carboxylase activities by stimulating adenosine monophosphate-activated protein kinase (AMPK). MWE attenuated the expression of sterol regulatory element-binding protein-1 (SREBP-1) and its target molecules, such as fatty acid synthase. Similar results were also measured in the expressions of enzymes involved in triglyceride and cholesterol biosyntheses including glycerol-3-phosphate acyltransferase, 3-hydroxy-3-methylglutaryl-CoA reductase, and SREBP-2. In contrast, the lipolytic enzyme expression of peroxisome proliferator activated receptor α and carnitine palmitoyltransferase-1 were increased. CONCLUSIONS: Our study suggests that the hypolipidemic effects of MWE occur via phosphorylation of AMPK and inhibition of lipid biosynthesis. Therefore, the mulberry extract may be active in the prevention of fatty liver.

Postmortem role of calpain-11 in ostrich skeletal muscle.

The postmortem calpain-11 role in ostrich muscle was investigated. Pairs of ostrich muscle (Iliotibialis cranialis) were excised from 32 ostrich carcasses in 3-h postmortem and randomly assigned into four treatments. The muscle was cut into 2.5-cm thick meat cores. The cores were incubated in 30 mM CaCl2, 30 mM EDTA, 90 mM NaCl, or control. The cores from the left-side carcasses were sampled after 0, 1, 2, and 3 days of incubation at 5 °C, while the right-side meat cores were taken at 1-day and 3-day incubation for shear force measurements. The results showed that the decrease in unautolyzed and total activities of calpain-11, desmin content and shear force was more rapid in CaCl2-incubated samples than in control, NaCl- and EDTA-incubated samples. Thus, present results suggest that in the absence of calpain-1, calpain-11 with an extensive activation by adding exogenous Ca2+ could enhance the postmortem proteolysis and tenderization of ostrich muscle.

Mulberry anthocyanins inhibit oleic acid induced lipid accumulation by reduction of lipogenesis and promotion of hepatic lipid clearance.

Mulberry (Morus alba L.) has been considered to possess different benefits such as protecting liver; improving fever, urine excretion disorder, hypertension, and diabetic syndrome; and preventing cardiovascular diseases. Recently, mounting evidence has shown that mulberry anthocyanin extract (MAE) is beneficial to hyperlipidemia; however, the mechanisms remain unclear. The present study was aimed to investigate the protective effects of MAE on hepatocyte cultured with high fatty acid and the underlying mechanisms. By using human hepatoma cell HepG2 as cell model, the results showed that MAE suppressed fatty acid synthesis and enhanced fatty acid oxidation, contributing to amelioration of lipid accumulation induced by oleic acid (OA). Moreover, MAE also inhibited acetyl coenzyme A carboxylase (ACC) activities by stimulating adenosine monophosphate-activated protein kinase (AMPK). MAE attenuated the expression of sterol regulatory element-binding protein-1 (SREBP-1) and its target molecules, such as fatty acid synthase (FAS). Similar results were also found in the expressions of enzymes involved in triglyceride and cholesterol biosyntheses including glycerol-3-phosphate acyltransferase (GPAT), 3-hydroxy-3-methyl-glutaryl CoA reductase (HMGCoR), adipocyte-specific fatty acid binding protein (A-FABP), and SREBP-2. In contrast, the lipolytic enzyme expressions of peroxisome proliferator activated receptor α (PPARα) and carnitinepalmitol- transferase-1 (CPT1) were increased. This study suggests the hypolipidemic effects of MAE occur via phosphorylation of AMPK and inhibition of lipid biosynthesis and stimulation of lipolysis. Therefore, the mulberry anthocyanins may actively prevent nonalcoholic fatty liver disease.