PK 11195 reduces the brain availability of lindane in rats and the convulsions induced by this neurotoxic agent

Cloning and expression of the translocator protein (18 kDa), voltage-dependent anion channel, and diazepam binding inhibitor in the gonad of largemouth bass (Micropterus salmoides) across the reproductive cycle

Cholesterol transport across the mitochondrial membrane is rate-limiting for steroidogenesis in vertebrates. Previous studies in fish have characterized expression of the steroidogenic acute regulatory protein, however the function and regulation of other genes and proteins involved in piscine cholesterol transport have not been evaluated. In the current study, mRNA sequences of the 18 kDa translocator protein (tspo; formerly peripheral benzodiazepine receptor), voltage-dependent anion channel (vdac), and diazepam binding inhibitor (dbi; also acyl-CoA binding protein) were cloned from largemouth bass. Gonadal expression was examined across reproductive stages to determine if expression is correlated with changes in steroid levels and with indicators of reproductive maturation. In testis, transcript abundance of tspo and dbi increased with reproductive maturation (6- and 23-fold maximal increase, respectively) and expression of tspo and dbi was positively correlated with reproductive stage, gonadosomatic index (GSI), and circulating levels of testosterone. Testis vdac expression was positively correlated with reproductive stage and GSI. In females, gonadal tspo and vdac expression was negatively correlated with GSI and levels of plasma testosterone and 17β-estradiol. Ovarian dbi expression was not correlated with indicators of reproductive maturation. These studies represent the first investigation of the steroidogenic role of tspo, vdac, and dbi in fish. Findings suggest that cholesterol transport in largemouth bass testis, but not in ovary, may be transcriptionally-regulated, however further investigation will be necessary to fully elucidate the role of these genes in largemouth bass steroidogenesis.

Biochemical effects induced by the hexachlorocyclohexanes

The hexachlorocyclohexanes (HCHs) are synthetic compounds that have been widely used for the control of pests. The most common HCH isomers are the α-, β-, δ-, and γ-HCH. Although the have the same chlorine substitution pattern, the spatial orientation of chlorine atoms is different on each one of them, resulting in unique structures that have distinct molecular properties. Humans are exposed to individual HCH isomers through various routes, including ingestion of contaminated water or food, absorbed through the skin or by inhalation, and because of their liposolubility, these chemicals are mostly stored in fat-containing tissues. The isomer-specific spectrum of biochemical actions for these compounds has been wee characterized for different endpoints such as enzyme activation, calcium homeostasis, gap junctional intercellular communication, endocrine disruption, and cancer, among others. The interaction with the GABA reception has been one of the most extensively studied properties of the HCHs. For instance, γ-HCH acts as a GABAA channel blocker, whereas α- and δ-HCH potentiate currents , all working as allosteric modulators of the receptor. The changes in calcium homeostasis elicited by HCHs are both isomer and cell type specific. For example, in neurons, both the δ- and γ-isomers of HCH stimulate Ca²+ influx through different voltage-gated Ca²+ channels. In human neutrophils, α-,δ-, and γ-HCH, but not β-HCH, increase intracellular Ca²+ concentrations. This isomer-dependent behavior is also similar to that observed for phospholipase A2 activation and also correlates with oxidative stress generation. On the other hand, there are several lines of evidence suggesting that HCHs alter genomic integrity, and, therefore, these compounds have been classified as possibly carcinogenic to humans . Finally, HCHs have been reported to be endocrine disrupters. In fact, γ- and β-HCH have been shown to have weak estrogenic activity, and together with the α- and the δ-isomer, also interfere with steroidogenesis. In short, the HCH isomers are good examples of structurally related chemicals, for which the geometrical patterns present in each one of the different conformers create structures that possess specific mechanisms of action and toxicological properties.

The evaluation of effect of alpha-lipoic acid and vitamin E on the lipid peroxidation, gamma-amino butyric acid and serotonin level in the brain of mice (Mus musculus) acutely intoxicated with lindane

The objective of the present study was to evaluate the neurotoxic effects of lindane, in mice and the protective potential of two antioxidants alpha-lipoic acid (ALA) and vitamin E, against the observed lindane induced toxicity. 7-8 weeks old healthy Swiss mice were administered acute doses of lindane (40 mg/kg b.w.) or antioxidants or both subcutaneously and analyzed 18 h later. ALA and vitamin E were used in the combination for neuroprotection in the concentration of 20 mg/kg b.w. and 50 mg/kg b.w. respectively. Lipid peroxidation, gamma-amino butyric acid (GABA) and serotonin level were used as biochemical test of toxic action for lindane induced acute toxicity. Protective effects of ALA and vitamin E were also evaluated on the same parameters. Reduced glutathione (GSH) and thiobarbituric acid reactive substances (TBARS) level served as an index for determining the extent of lipid peroxidation. Treatment of lindane to normal control animals resulted in a significant decrease and increase in GSH (P<0.01) and TBARS level (P<0.01) respectively in crude homogenate of whole brain. Antioxidants treatment significantly altered the level of GSH (P<0.01) and TBARS (P<0.01). GABA and serotonin level in whole brain as well as in different regions of brain were measured. Main brain regions under the investigation were olfactory lobe, cerebrum, hippocampus-hypothalamus, cerebellum and pons-medulla. Critical difference (CD) of GABA level in various groups was found significant at 1% in cerebrum and hippocampus-hypothalamus, at 5% in whole brain, cerebellum and pons-medulla (i.e. P<0.01 and P<0.05 respectively). Change in serotonin level in whole brain as well as in all studied brain regions of various groups was found significant at 1% CD (i.e. P<0.01).