Sex Differences in Hippocampal Neuronal Sensitization by Nicotine in M. gerbils.

We studied the sex different nicotine effect on evoked population spike amplitudes (ePSA) and connexin (Cx) expression in the hippocampus CA1 area of gerbils. Acute doses of nicotine bitartrate (0.5 mg/kg: NT-0.5) slightly reduced ePSA in males but markedly augmented that in females. Acute NT (5.0 mg/kg) markedly increased the ePSA in all gerbils. Unlike acute NT-0.5, repeated NT-0.5 injection (twice a day for 7 days) significantly increased the ePSA in males and slightly affected the NT-0.5 effect in females. The Cx36 and Cx43 expression levels as well as Cx expressing neuronal populations were significantly increased by repeated NT-0.5 in in both male and female gerbils, and particularly, Cx43 expression was somewhat prominent in females. These results demonstrated a sex difference with respect to the nicotine effect on hippocampal bisynaptic excitability, irrelevant to connexin expression.

Proteome analysis of the anti-inflammatory response of flavonoids isolated from Korean Citrus aurantium L. in lipopolysaccharide-induced L6 rat skeletal muscle cells.

Skeletal muscle is an important organ in our body and a dynamic composite of proteins. Citrus aurantium L. has been widely used in oriental medicine in Eastern Asia for a long time. It contains over 100 bioactive compounds and flavonoids that regulate the inflammatory response and tumorigenesis, through various mechanisms. In the present study, we investigated changes in the protein pattern using two-dimensional electrophoresis (2-DE) and matrix assisted laser desorption ionization time of flight mass spectroscopy (MALDI-TOF/MS) to assess the anti-inflammatory effect of flavonoids isolated from Korean C. aurantium L. in lipopolysaccharide (LPS)-induced L6 cells. L6 skeletal muscle cells were pretreated with flavonoids for 1 h and stimulated with LPS for 24 h. Proteins from the L6 cells of the control, LPS treated and flavonoid treated groups were extracted and resolved by 2-DE using pH 4-7 IPG strips loaded with 150 µg of protein. Forty-one differentially expressed protein spots were identified (more than two-fold was considered significant, p < 0.05), and 18 were detected by MALDI-TOF/MS. These results suggest that proteomics can be used to identify changes in the expression of marker proteins and the anti-inflammatory effect of flavonoids isolated from Korean C. aurantium L.

Biological and antibacterial activities of the natural herb Houttuynia cordata water extract against the intracellular bacterial pathogen salmonella within the RAW 264.7 macrophage.

Salmonellosis is a major bacterial zoonosis that causes a variety of disease syndromes, from self-limiting enteritis to fatal infection in animals and food-borne infection and typhoid fever in humans. Recently, the emergence of multidrug-resistant strains of Salmonella sp. has caused more serious problems in public health. The present study investigated the antibacterial effects of Houttuynia cordata water extract (HCWE) against murine salmonellosis. In RAW 264.7 cells, there was no detectable cytotoxic effect of HCWE at any concentration between 25 and 100 microg/ml after 8-h incubation. The antibacterial activity of HCWE was then examined in a Salmonella enterica serovar (Salmonella typhimurium), and was found to increase in a dose-dependent manner at concentrations from 25 to 100 microg/ml during 8-h incubation. HCWE also affected RAW 264.7 cells including morphologic change and bacterial uptake, but there was no significant difference in bacterial replication in RAW 264.7 cells. With HCWE alone, nitric oxide (NO) production by RAW 264.7 cells did not increase, but when RAW 264.7 cells were infected by S. typhimurium, with or without HCWE, NO production with HCWE was 2-fold higher than that without HCWE. Treatment with HCWE did not affect inducible NO synthase (iNOS) mRNA expression by RAW 264.7 cells, but when RAW 264.7 cells with HCWE were infected by S. typhimurium, iNOS mRNA expression was increased during 8-h incubation. Furthermore, HCWE showed virulence reduction effects in S. typhimurium-infected BALB/c mice. After a lethal dose of S. typhimurium, the mortality rate in the HCWE untreated group was 100% at 7 d, but the HCWE 25, 50, and 100 microg/ml groups survived until 11, 17, and 23 d, respectively. These data suggest that HCWE is stable and beneficial in the treatment of bacterial infection including intracellularly replicating pathogens and may solve antimicrobial misuse and overuse.