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Abstract : Some serotonin 5‐HT3 receptor ligands of tropeine structure have been recently shown to modulate ionophore function and binding of glycine receptors. This led us to study the effects of the tropeines tropisetron and atropine on recombinant human glycine receptors transiently expressed in Xenopus oocytes by using whole‐cell voltage‐clamp electrophysiology. Glycine currents were inhibited by atropine in an apparently competitive manner and with considerable selectivity of the tropeines for α2 versus α1 subunits. Coexpression of β with α subunits and replacement of the N‐terminal region of the α1 subunits by the corresponding β segment resulted in similar increases in the inhibitory potencies. Our data suggest common sites of the tropeines for inhibition on the N‐terminal region of glycine receptors. The point mutations R271K and R271L of the α1 subunit decreased, whereas a T112A substitution increased, the inhibition constants (Ki) of the tropeines. These changes in the Ki values of the tropeines were associated with opposite changes in the EC50 of glycine. Selectivities for the tropeines versus glycine (EC50/Ki) varied within three orders of magnitude. These results, when expressed in terms of free energy changes, can be interpreted according to a two‐state receptor model.

Chemotherapy is a conventional treatment for glioma, but its efficacy is greatly limited due to low blood-brain barrier (BBB) permeability and lack of specificity. Herein, intelligent and tumor microenvironment (TME)-responsive folic acid (FA) derivatives and mitochondria-targeting berberine (BBR) derivatives co-modified liposome coated with Tween 80 loading paclitaxel (PTX-Tween 80-BBR + FA-Lip) was constructed. Specifically speaking, liposomes modified by FA can be effectively target ed to glioma cells. BBR, due to its delocalized positive electricity and lipophilicity, can be attracted by mitochondrial membrane potential and concentrate on mitochondria to achieve mitochondrial targeting and induce cell apoptosis. By simultaneously modifying the liposome with FA and BBR to deliver drugs, leads to a good therapeutic effect of glioma through FA-based glioma targeting and BBR-based mitochondrial targeting. In addition, the surface of the liposome was coated with Tween 80 to further improve BBB penetration. All results exhibited that PTX-Tween 80-BBR + FA-Lip can observably improve the chemotherapy therapeutic efficacy through the highly specific tumor targeting and mitochondrial targeting, which can provide new ideas and methods for the targeted therapy of glioma.

1. The effect of 10 g 5,7-dihydroxytryptamine (5,7-DHT) micro-injected into both the dorsal (DRN) and the median raphe nuclei (MRN) on the intake of ethanol in the low alcohol drinking (LAD) rat was measured using a standard 3-30% ethanol preference test. 2. The combined lesion of both midbrain structures depleted the levels of serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) significantly in each of eight major regions of the brain. The levels of norepinephrine, dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) remained unchanged after the lesion. 3. The effects of the neurotoxin lesions on the intakes of ethanol, food, water and total amount of fluid consumed were not significant. 4. The results corroborate our previous findings with the Sprague-Dawley strain of rat and suggest that although brain 5-HT may play a role in the maintenance of basal patterns of ethanol drinking, this monoamine may not be able to modify further the consumption of this fluid after lesioning with 5,7-DHT.

Brain-to-blood transport, or efflux, systems play important roles in brain functions and can affect the CNS uptake and activity of endogenous and exogenous blood-borne substances. Several efflux systems have been described for peptides. These efflux systems may play important roles in communication between the CNS and peripheral tissues and may be important in conditions such as alcoholism.

AbstractNon‐adaptive activation of dopamine transmission in the nucleus accumbens shell by drugs of abuse has been attributed a fundamental role in the mechanism of drug addiction. In order to test this hypothesis, we compared in the same subject the effect of an addictive drug (ethanol) and of taste stimuli, including ethanol's own taste, on dialysate dopamine in the nucleus accumbens shell as an estimate of dopamine transmission and on taste reactivity as an expression of motivational valence. Ethanol was also monitored in the dialysates. In naive rats, intraoral infusion of a 20% sucrose + chocolate solution elicited a monophasic increase of dialysate dopamine immediately after the intraoral infusion. In contrast, intraoral infusion of 10% ethanol, 10% ethanol + 20% sucrose or 10% ethanol + 20% sucrose + chocolate solutions elicited a biphasic increase of nucleus accumbens dopamine with an early taste‐related rise and a late rise related to dialysate ethanol. Pre‐exposure to the ethanol solutions 24 h before resulted in the absence of the early dopamine rise and permanence of the late dopamine rise. This late dopamine rise was actually increased as compared with that of the nonpre‐exposed group when sucrose‐containing ethanol solutions were tested. The results indicate that single trial pre‐exposure to the ethanol solutions differentially affects the responsiveness of nucleus accumbens shell dopamine to the direct intracerebral action of ethanol and to the effect of its taste with potentiation, or no change of the first and abolition of the second. These observations point to the existence of major differences in the adaptive regulation of nucleus accumbens dopamine transmission in the shell after drug as compared with taste reward. These differences, in turn, are consistent with a role of nucleus accumbens shell dopamine in the mechanism of the behavioural effects of addictive drugs.

Platelet aggregation, secretion of serotonin, and formation of thromboxane B2 induced by platelet-activating factor (1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine) were studied in plasma containing physiological concentrations of ionized calcium in eight alcoholics after cessation of heavy drinking. Responses of platelets of four nonalcoholic volunteers, matched with a subgroup of the alcoholics by age and sex, were also investigated. Aggregation of platelets from alcoholics was significantly less throughout the 6-day detoxification period compared with controls. Secretion of serotonin (5-hydroxy-tryptamine) was negligible and the production of thromboxane B2 was not detectable. Decreased platelet aggregability in response to aggregating agents, including platelet-activating factor, may be important in the development of hemorrhagic complications in alcoholics.

The effect of ethanol in vitro on inositol lipid metabolism in brain slices was investigated under nonstimulating and stimulating conditions. In cerebral cortical slices 100 microM norepinephrie (NE), 1 mM carbachol, 100 microM serotonin, 20 mM KCl, 1 mM glutamate and 30 microM A23187 stimulated inositide hydrolysis as measured by the release of [3H]inositol phosphates from [3H]myoinositol labeled slices. Ethanol (500 mM) inhibited nonstimulated inositide hydrolysis but had variable effects on stimulated inositide breakdown. NE-, KCl- and glutamate-stimulated [3H]inositol phosphate release was inhibited by 500 mM ethanol in the cortex. The inhibitory effect of ethanol on NE-stimulated inositide hydrolysis was concentration dependent and significant at concentrations as low as 100 mM. Inhibition by ethanol appeared to be noncompetitive. A similar pattern of inhibition by ethanol was observed when KCl was the stimulant. In hippocampal and hypothalamic slices, similar to cortical slices. NE- and KCl-stimulated inositide breakdown was significantly inhibited by ethanol. However, in brain stem slices, only KCl-stimulated [3H]inositol phosphate release was inhibited. Striatal slices stimulated by carbachol, NE and KCl were sensitive to the inhibitory effects of ethanol on inositol lipid breakdown. These results suggest that ethanol in vitro has specific effects on inositol lipid metabolism depending on the brain region studied and the type of stimulation. Moreover, the differential sensitivity to ethanol of stimulated inositide hydrolysis in the brain may contribute, at least in part, to some of the pharmacological effects of ethanol in vivo.

Background:  Ethanol (ETOH) consumption by pregnant women can result in Fetal Alcohol Spectrum Disorder (FASD). To date, the cellular targets and mechanisms responsible for FASD are not fully characterized. Our aim was to determine if ETOH can affect fetal human brain‐derived neural progenitor cells (NPC).Methods:  Neural progenitor cells were isolated by positive selection from normal second trimester fetal human brains (n = 4) and cultured, for up to 72 hours, in mitogenic media containing 0, 1, 10, or 100 mM ETOH. From 48 to 72 hours in culture, neurospheres generated in these conditions were filmed using time‐lapse video microscopy. At the end of 72 hours, neurosphere diameter and roundness were measured using videographic software. Mitotic phase analysis of cell‐cycle activity and apoptotic cell count were also performed at this time, by flow cytometry using propidium iodide (PI) staining. Real‐time PCR was used to estimate expression of genes associated with cell adhesion pathways.Results:  Neurosphere diameter correlated positively (r = 0.87) with increasing ETOH concentrations. There was no significant difference in cell‐cycle activity and no significant increase in apoptosis with increasing ETOH concentrations. Time‐lapse video microscopy showed that ETOH (100 mM) reduced the time for neurosphere coalescence. Real‐time PCR analysis showed that ETOH significantly altered the expression of genes involved in cell adhesion. There was an increase in the expression of α and β Laminins 1, β Integrins 3 and 5, Secreted phosphoprotein1 and Sarcoglycan ε. No change in the expression of β Actin was observed while the expression of β Integrin 2 was significantly suppressed.Conclusions:  ETOH had no effect on NPC apoptosis but, resulted in more rapid coalescence and increased volume of neurospheres. Additionally, the expression of genes associated with cell adhesion was significantly altered. ETOH induced changes in NPC surface adhesion interactions may underlie aspects of neurodevelopmental abnormalities in FASD.

Neuronal death is an active process that results in the upregulation of antigens recognized by ALZ-50 and p53. Since prenatal exposure to ethanol can induce the postnatal death of cortical neurons, we examined the effects of ethanol on the in vivo expression of both the ALZ-50-positive antigen and p53. Pregnant rats were fed one of three diets, a liquid diet containing ethanol (Et), an isocaloric and isonutritive diet (Ct), or chow and water (Ch). Segments of frontoparietal cortex from fetuses and pups were examined for ethanol-induced changes (a) in the expression of ALZ-50 and p53 immunoreactivity using a quantitative immunoblotting assay and (b) in the distribution of ALZ-50- and p53-positive cells using immunohistochemistry. In control rats, ALZ-50 identified a 56-kDa peptide that was transiently expressed postnatally and peak expression occurred on postnatal day (P) 6 to P12. In Et-treated rats, peak expression was attained earlier (on P3) and was about three times of that achieved in the controls. The anti-p53 antibody identified three proteins (28, 56, and 58 kDa). Peak expression in control rats occurred during the second postnatal week and only the 58-kDa protein was expressed in appreciable amounts in adult cortex. Each p53-positive protein was affected by ethanol exposure. The 28- and 56-kDa p53-positive proteins were affected by ethanol much in the same way as was the ALZ-50-positive antigen. That is, the timing and amount of peak expression were earlier and lower, respectively, in the Et-treated rats. The postnatal expression of the 58-kDa protein was halved following prenatal exposure to ethanol. Both ALZ-50 and anti-p53 immunoprecipitated proteins are p53- and ALZ-50-positive, respectively. Thus, ethanol alters the expression of the ALZ-50- and p53-positive proteins and presumably the timing of neuronal death in the developing cortex. The parallel effects of prenatal ethanol exposure on the 56-kDa ALZ-50-positive antigen and the 28- and 56-kDa p53-positive proteins and the coprecipitation of the proteins are consistent with the notion that ALZ-50 recognizes a form of p53.