Unusual emission properties of the selected organosilicon compounds containing a styryl-carbazole chromophore: inversion of the singlet excited states.

The spectroscopic and photophysical properties of silicon-containing styryl-carbazole were investigated in various solvents, and the results were analyzed with reference to its carbon derivatives. In n-hexane, both the silicon- and the carbon-containing compounds had very similar emission properties. In acetonitrile, the emission properties remained the same for the C-compound but changed significantly for the Si-compounds. In particular, the fluorescence spectra of the latter were red-shifted, and their radiative rate constants were even 7 times larger than in n-hexane, which suggested that the emissive states of the silicon-containing compounds were different in these two solvents. DFT calculations using the CAM-B3LYP functional showed that the emissive state of the C-compound involves the LUMO+1 orbital regardless of the medium. In contrast, for the Si-compound, changing the medium from n-hexane to acetonitrile resulted in the inversion of the emissive states from an excited state involving the LUMO+1 orbital (the dipole moment µ = 4.2 D) to an excited state involving the LUMO orbital (µ = 8.9 D).

Ceramide galactosyltransferase (UGT8) is a molecular marker of breast cancer malignancy and lung metastases.

BACKGROUND: It was shown recently on the level of gene expression that UGT8, coding UDP-galactose:ceramide galactosyltransferase, is one of six genes whose elevated expression correlated with a significantly increased the risk of lung metastases in breast cancer patients. In this study primary tumours and their lung metastases as well as breast cancer cell lines were analysed for UGT8 expression at the protein level. METHODS: Expression of UGT8 in breast cancer tissue specimens and breast cancer cell lines was analysed using IHC, real-time PCR and Western blotting. RESULTS: Comparison of the average values of the reaction intensities (IRS scale) showed a significant difference in UGT8 expression between (1) primary and metastatic tumours (Mann-Whitney U, P<0.05), (2) tumours of malignancy grades G3 and G2 (Mann-Whitney U, P<0.01) as well as G3 and G1 (Mann-Whitney U, P<0.001) and (3) node-positive and node-negative tumours (Mann-Whitney U, P<0.001). The predictive ability of increased expression of UGT8 was validated at the mRNA level in three independent cohorts of breast cancer patients (721). Similarly, breast cancer cell lines with the 'luminal epithelial-like' phenotype did not express or weakly expressed UGT8, in contrast to malignant, 'mesenchymal-like,' cells forming metastases in nude mice. CONCLUSION: Our data suggest that UGT8 is a significant index of tumour aggressiveness and a potential marker for the prognostic evaluation of lung metastases in breast cancer.

SOD1/Rag2 Mice with Low Copy Number of SOD1 Gene as a New Long-Living Immunodeficient Model of ALS.

The most recent research concerning amyotrophic lateral sclerosis (ALS) emphasizes the role of glia in disease development. Thus, one can suspect that the effective therapeutic strategy in treatment of ALS would be replacement of defective glia. One of the basic problems with human glial progenitors (hGRPs) replacement strategies is the time needed for the cells to become fully functional in vivo. The lifespan of most popular high copy number SOD1 mutant mice might be too short to acknowledge benefits of transplanted cells. We focused on developing immunodeficient rag2-/- model of ALS with lower number of transgene copies and longer lifespan. The obtained hSOD1/rag2 double mutant mice have been characterized. QPCR analysis revealed that copy number of hSOD1 transgene varied in our colony (4-8 copies). The difference in transgene copy number may be translated to significant impact on the lifespan. The death of long- and short-living hSOD1/rag2 mice is preceded by muscular weakness as early as one month before death. Importantly, based on magnetic resonance imaging we identified that mutant mice demonstrated abnormalities within the medullar motor nuclei. To conclude, we developed long-living double mutant hSOD1/rag2 mice, which could be a promising model for testing therapeutic utility of human stem cells.

Preclinical characterization of selective phosphodiesterase 10A inhibitors: a new therapeutic approach to the treatment of schizophrenia.

We have recently proposed the hypothesis that inhibition of the cyclic nucleotide phosphodiesterase (PDE) 10A may represent a new pharmacological approach to the treatment of schizophrenia (Curr Opin Invest Drug 8:54-59, 2007). PDE10A is highly expressed in the medium spiny neurons of the mammalian striatum (Brain Res 985:113-126, 2003; J Histochem Cytochem 54:1205-1213, 2006; Neuroscience 139:597-607, 2006), where the enzyme is hypothesized to regulate both cAMP and cGMP signaling cascades to impact early signal processing in the corticostriatothalamic circuit (Neuropharmacology 51:374-385, 2006; Neuropharmacology 51:386-396, 2006). Our current understanding of the physiological role of PDE10A and the therapeutic utility of PDE10A inhibitors derives in part from studies with papaverine, the only pharmacological tool for this target extensively profiled to date. However, this agent has significant limitations in this regard, namely, relatively poor potency and selectivity and a very short exposure half-life after systemic administration. In the present report, we describe the discovery of a new class of PDE10A inhibitors exemplified by TP-10 (2-{4-[-pyridin-4-yl-1-(2,2,2-trifluoro-ethyl)-1H-pyrazol-3-yl]-phenoxymethyl}-quinoline succinic acid), an agent with greatly improved potency, selectivity, and pharmaceutical properties. These new pharmacological tools enabled studies that provide further evidence that inhibition of PDE10A represents an important new target for the treatment of schizophrenia and related disorders of basal ganglia function.

Selective cholinergic lesions in the rat nucleus basalis magnocellularis with limited damage in the medial septum specifically alter attention performance in the five-choice serial reaction time task.

Selective immunotoxic cholinergic lesions in the nucleus basalis magnocellularis (NBM) impair visuospatial attention performance in a 5-choice serial reaction time task (5-CSRT task). The features of the reported deficits, however, do not perfectly match among studies, in which some lesions may have been too weak while others largely encroached onto the septal region. Using the 5-CSRT task, we therefore re-assessed the effects of NBM lesions that produced minimal septal damage. Long-Evans adult male rats were trained to stable 5-CSRT task performance (stimulus duration: 0.5 s) and subsequently subjected to intra-NBM injections of 192 IgG-saporin (200 ng/side). The lesions induced more than 90% loss of choline acetyltransferase-positive neurons in the NBM vs. only 28% in the medial septum. The decrease of the optical density of acetylcholinesterase reaction products was significant in the cortex (-91%), not in the hippocampus. In the 5-CSRT task, the lesions resulted in increased omissions (from 10% to 30%) and decreased correct responses (from 80% to 60%), with negligible or no effects on all other usually collected variables. This deficit disappeared with lengthened stimulus duration (i.e. 0.5-1 and then 5 s). Furthermore, overall performance levels decreased when the stimulus duration was shortened (i.e. 0.5-0.2 s) or its intensity attenuated, and rats with cholinergic lesions remained consistently impaired vs. controls. These results show that disruption of sustained visual attention functions by damage to the NBM cholinergic neurons can be evidenced despite weak or no effects on variables accounting for motivational, locomotion- or impulsivity-related biases. Discrepancies with previously reported results are discussed in terms of differences in lesion extent/specificity and training levels.

Environmental enrichment increases responding to contextual cues but decreases overall conditioned fear in the rat.

This study aimed at investigating the effects of environmental enrichment on various aspects of contextual processing in adult female rats. In experiment 1, simple conditioning was studied using either a training procedure allowing overshadowing of the contextual cues by signalling footshock with a discrete tone or a training procedure allowing a reduction of this overshadowing by explicitly unpairing the footshock and the tone. In experiment 2, contextual discrimination and contextual occasion-setting were assessed. Rats were daily exposed to two different contexts. In one context, a footshock was delivered 30s after the offset of a tone, whereas in the other context the same tone was presented alone. Experiment 3 examined familiarization to a new context. Experiment 1 showed that environmental enrichment reduced the overshadowing of contextual cues by the tone and also reduced freezing to the more predictive cue according to the training procedure used. Experiment 2 showed that environmental enrichment increased the ability of rats to discriminate two contexts. Experiment 3 showed that enriched rats familiarized faster to a new context than standard rats. Taken together, these results suggest that environmental enrichment in adult rats enhances learning about contextual cues and reduces overall fear associated with aversive events.

Cholecystokinin stimulates aldosterone secretion from dispersed rat zona glomerulosa cells, acting through cholecystokinin receptors 1 and 2 coupled with the adenylate cyclase-dependent cascade.

Cholecystokinin is a regulatory peptide, that acts through two subtypes of receptors, 1 and 2. RT-PCR demonstrated the expression of both cholecystokinin receptors 1 and 2 genes in the zona glomerulosa, but not the zona fasciculata-reticularis, of rat adrenals. Autoradiography demonstrated the presence of abundant [(125)I]cholecystokinin-binding sites in the zona glomerulosa, but not the zona fasciculata-reticularis, which were displaced by both cholecystokinin receptor 1- and 2-selective antagonists (cholecystokinin 1-A and 2-A). Cholecystokinin increased basal aldosterone secretion from dispersed zona glomerulosa cells without affecting corticosterone secretion from zona fasciculata-reticularis cells. The aldosterone response to cholecystokinin was blunted by cholecystokinin 1-A and 2-A, which when added together abolished it. ACTH-stimulated aldosterone production was not affected by cholecystokinin; in contrast, cholecystokinin potentiated aldosterone response to both angiotensin II and K(+). Cholecystokinin enhanced cAMP, but not IP(3), release by dispersed zona glomerulosa cells. The aldosterone response to cholecystokinin was abolished by the adenylate cyclase inhibitor SQ-22536 and the PKA inhibitor H-89, but not by either the PLC inhibitor U-73122 or the PKC inhibitor calphostin C. In conclusion, our study provides evidence that cholecystokinin, acting through cholecystokinin receptors 1 and 2 coupled with the adenylate cyclase/PKA cascade, exerts a sizeable secretagogue action on rat zona glomerulosa cells.

The anorectic effects of CRH and restraint stress decrease with repeated exposures.

Intracerebroventricular (icv) administration of corticotropin-releasing hormone (CRH) or exposure to a restraint stressor causes acute anorexia in rats. However, the effects on food intake of repeated injections of CRH or repeated exposures to restraint stress have not been previously reported. As the effects of these more chronic CRH and stress treatments may be of greater relevance to emerging hypotheses of the pathogenesis of human eating and affective disorders, we measured the changes in food intake and body weight of rats after repeated central injections of CRH. In two experiments using two different daily dosages of CRH and two different schedules of administration, we found that the anorectic effect of CRH decreased over repeated injections. Weight gain was slowed significantly only in the high-dose experiment. Rats may become tolerant to the anorectic effects of CRH delivered by repeated icv injections. These findings have important implications for hypothesized mechanisms of anorexia nervosa and/or depression.

Chronic treatment with amitriptyline produces supersensitivity to nicotine.

The authors used a thermoregulation paradigm to evaluate effects of amitriptyline (AMI) on the sensitivity of a nicotinic mechanism involved in the regulation of core temperature in rats. Treatment with this tricyclic was associated with a significant increase in the hypothermic response to nicotine. Supersensitivity persisted for a minimum of 7.5 days following the last dose of AMI, and a significant proportion of animals displayed increased sensitivity after 14.5 days of abstinence. Implications for the mechanism of action of AMI are highlighted.

Bilateral lesions of the entorhinal cortex differentially modify haloperidol- and olanzapine-induced c-fos mRNA expression in the rat forebrain.

Lesions of the entorhinal cortex are now an accepted model for mimicking some of the neuropathological aspects of schizophrenia, since evidence has accumulated for the presence of cytoarchitectonic abnormalities within this cortex in schizophrenic patients. The present study was undertaken to address the functional consequences of bilateral entorhinal cortex lesions on antipsychotic-induced c-fos expression. After a 15-day recovery period, the effect of a typical antipsychotic, haloperidol (1 mg/kg), on c-fos mRNA expression was compared with that of an atypical one, olanzapine (10 mg/kg), in both sham-lesioned and entorhinal cortex-lesioned rats. In sham-lesioned rats, both haloperidol and olanzapine induced c-fos expression in the caudal cingulate cortex, dorsomedial and dorsolateral caudate-putamen, nucleus accumbens core and shell and lateral septum. In addition, olanzapine, but not haloperidol, increased c-fos expression within the central amygdala. In entorhinal cortex-lesioned rats, haloperidol-induced c-fos expression was markedly reduced in most areas. In contrast, the olanzapine-induced c-fos expression was not altered in the nucleus accumbens shell and lateral septum of the lesioned rats. These findings reveal that entorhinal cortex lesions affect c-fos expression in a compound- and regional-dependent manner. Our results further emphasize the importance of the exploration of the mechanisms of action of antipsychotic drugs in the context of an associated cortical pathology.

Effects of a selective mu opioid receptor agonist and naloxone on the intake of sodium chloride solutions.

Endogenous opioid peptides are thought to play a role in mediating the palatability or rewarding aspects of sweet tastes. There is also evidence, however, which suggests that opioids may influence the preference for the taste of salt as well. In the present studies, we measured the effects of central administration of naloxone and the mu agonist [D-Ala2,MePhe4,Gly-ol5]enkephalin (DAGO) on the ingestion of salt solutions. In non-deprived rats given a choice of water and 0.6% saline, ICV injections of DAGO (1 and 3 nmol) significantly increased the intake of 0.6% saline; baseline water intake was minimal and was unaffected by DAGO. When rats were given a choice between water and 1.7% saline, DAGO stimulated both water and saline intake. Because 1.7% saline is a hypertonic solution, the increase in water intake may have been secondary to saline intake. In rats on a deprivation schedule in which water and 0.6% saline were available for only 2-3 h/day, there was a tendency for DAGO to increase 0.6% saline intake and decrease water intake, though these effects were not significant. In rats given water and 1.7% saline, DAGO increased saline intake and had no effect on water intake. Naloxone was also tested in water-deprived rats. Naloxone (20 and 50 micrograms) significantly decreased 0.6% saline intake; baseline water intake was low (3-5 ml) and was unaffected by naloxone. When rats were given a choice between water and 1.7% saline, naloxone (50 micrograms) significantly reduced water intake, while intake of 1.7% saline was slightly increased. These results suggest a role for central mu opioid receptors in mediating the preference for salt solutions.

Effects of systemic and intracerebroventricular administration of mecamylamine, a nicotinic cholinergic antagonist, on spatial memory in rats.

The effects of both systemic and intracerebroventricular administration of mecamylamine, a nicotinic antagonist, were tested on the Morris water maze performance of rats. In experiment 1, mecamylamine (0, 3, and 10 mg/kg, IP) was administered before daily training sessions on the Morris water maze, a task in which rats use environmental cues to learn the location of an invisible escape platform in a large pool of water. The escape latencies of rats given the higher dose of mecamylamine were significantly longer than the latencies of rats given either saline or the peripherally-acting nicotinic antagonist hexamethonium (10 mg/kg). Analysis of search patterns during a free swim trial conducted in the absence of an escape platform confirmed the disruptive effects of the higher dose of mecamylamine. Similar drug effects were not observed when these rats were trained to a visible platform, and mecamylamine did not affect the retrieval of spatial information in well-trained rats. In experiment 2, similar effects were observed with ICV administration of mecamylamine (0, 10, 30, and 100 micrograms). The two higher doses increased escape latencies during the last day of place training and all three doses significantly impaired performance on a free swim. No significant effects were noted on subsequent training to a visible platform, and only the highest dose marginally impaired the retrieval of spatial information in well-trained animals. Thus, mecamylamine appears to impair the acquisition of spatial information in the Morris water maze but does not affect retrieval of previously acquired spatial information at comparable doses.

Mecamylamine pretreatment increases subsequent nicotine self-administration as indicated by changes in plasma nicotine level.

Acute administration of mecamylamine, a centrally active nicotinic cholinergic agonist, has been shown to increase amount of smoking as indicated by smoking topography (e.g., puff rate, puff duration), expired carbon monoxide changes, and other inferential measures. In the present study, subjects showed significantly greater increases in plasma nicotine following smoking of two high-nicotine research cigarettes when pretreated with mecamylamine than when pretreated with placebo, even though no significant differences in puff volume or puff number were detected. Interestingly, none of our subjects reported nausea, although some achieved plasma nicotine levels at which nausea would typically be expected. We attribute the observed increases in nicotine intake to compensatory behavior designed to overcome mecamylamine's blocking effects.

Effects of bombesin on the morphology and function of the rat adrenal cortex: comparison of the acute and chronic responses.

The acute and chronic effects of bombesin (BM) on the structure and function of rat adrenal cortex were investigated by morphometric and radioimmunological techniques. An intraperitoneal bolus injection of 2 micrograms/rat BM markedly raised plasma corticosterone (B) concentration (PBC). The intraperitoneal BM infusion (1 microgram/rat.h-1) for 1, 2 or 4 days evoked a notable increase in the number of adrenocortical cells, without inducing apparent changes in either PBC or B output by adrenal quarters. Since proliferation and expression of specialized functions are mutually exclusive states of cells, our findings suggest that the conspicuous stimulation of adrenocortical-cell proliferation evoked by BM infusion may be responsible for the apparent lack of effect of this treatment on B secretion.

Effects of neurotensin and bombesin on the secretory and proliferative activity of regenerating rat adrenal cortex.

Neurotensin (NT) and bombesin (BM)-like peptides are known to be involved in the regulation of the rat hypothalamo-pituitary-adrenal axis. By using selective NT- and BM-receptor antagonists (NT-A and BM-A, respectively) we investigated whether endogenous NT and BM-like peptides play a role in the control of rat adrenal secretion and growth during enucleation-induced regeneration. At day 5 of regeneration, NT-A did not affect the plasma concentrations of aldosteronc (PAC) and corticosterone (PBC), but at day 8, it raised both PAC and PBC over the respective baseline value; the simultaneous administration of NT abolished this effect of NT-A. BM-A did not alter PAC and PBC at day 5 of regeneration, while at day 8 it enhanced PBC, an effect reversed by BM. NT-A did not alter mitotic index, and BM-A lowered it at both day 5 and day 8 of regeneration, an effect suppressed by the simultaneous administration of BM. Collectively, these findings allow us to draw the following conclusions: 1) endogenous NT and BM-like peptides influence adrenocortical regeneration in rats; 2) NT exerts a tonic inhibitory action on both aldosterone and corticosterone secretion, without affecting cell-proliferation rate; and 3) BM-like peptides exert a tonic suppressive effect on corticosterone production, coupled with a clear-cut stimulating effect on cell proliferation.

Factors influencing structure and function of intracerebral grafts in the mammalian brain: a review.

After twenty years of intensive research, the possibility to induce recovery from various disorders in brain damaged mammals by means of intracerebral grafts of fetal CNS tissue is well documented and largely accepted by the scientific community. However, there are several reports on animal research suggesting that intracerebral grafts may fail to induce the expected recovery after brain injury or even that they may cause deficits which are actually more pronounced than those induced by the lesions alone. In addition, attempts to produce functional benefits with catecholamine-releasing tissue grafts in the brain of Parkinsonian patients have given limited and variable results; graft-induced deleterious effects have also been occasionally reported in a few clinical cases. One way to progress towards a better understanding of such disappointing, although informative, discrepancies between successful and less successful experimental studies and clinical trials would be to consider that there are several factors which may influence, in one direction or the other, the survival, development, integration and functional expression of intracerebral fetal CNS grafts. The present review considers the following factors: (i) some of the technical factors such as the constraints of transplantation surgery, the origin of donor tissue, the implantation site, the age of both the donor and the recipient, and tissue manipulations prior to grafting (i.e., cryopreservation, culture, genetic modification); (ii) exogenous and endogenous neurotrophic factors, the latter being distinguished by whether they may be host- or graft-derived; (iii) immunological factors (from the particular immunological status of the brain to some effects of immunosuppression in the case of xenografting)', (iv) pharmacological factors, with a particular focus on experimental data suggesting that administration of drugs may or might contribute to elicit, enhance or block some functional effects of grafts. It is concluded that all these factors may become simultaneously operative and interacting, thereby presiding over the functional outcome of intracerebral grafting in both experimental research and clinical trials.

Chronic infusion of GABA and saline into the nucleus basalis magnocellularis of rats: II. Cognitive impairments.

In order to assess sensorimotor and/or cognitive modifications following chronic inhibition of nucleus basalis magnocellularis (NBM) neurons, rats trained in two radial maze paradigms (the classical version of the test and a modified version introducing a one-hour delay between the fourth and the fifth choice) received chronic infusion of gamma-aminobutyric acid (GABA) into the NBM area. GABA (10 and 50 micrograms/microliters/h) was infused for 3 days into the NBM contralateral to their preferred turning direction in the radial maze. Simultaneously, saline (NaCl 0.9%; 1 microliter/h) was infused into the contralateral NBM. GABA and saline infusions were alternated for the subsequent 3-day period. One week later, we investigated the rats' ability to learn a multiple trial passive avoidance task. At the dose of 50 micrograms/microliters, GABA infusion produced (1) a turning bias ipsilateral to the side first infused with GABA, (2) transitory cognitive impairments in radial maze tasks and (3) a deficit in the acquisition of the passive avoidance task. At the dose of 10 micrograms/microliters, the same behavioral deficits were observed except that (1) the turning bias was reversed by the contralateral GABA infusion and (2) cognitive impairments in the radial maze were observed only when a delay was inserted between the fourth and the fifth choice. Histologically, we found a dose-dependent gliosis in the NBM area first infused with GABA. These data suggest a reactivity of the NBM to GABAergic manipulations and the intervention of this structure in both sensorimotor and cognitive processes involved in the radial maze paradigms.

Effects of nicotine on spatial memory deficits in rats with septal lesions.

Impaired septohippocampal function has been implicated in the memory deficits associated with Alzheimer's disease (AD), and septal lesions have been used to model the cognitive deficits associated with AD. In this study, we assessed the effects of systemic administration of nicotine on lesion-induced deficits in the acquisition of a spatial discrimination version of the Morris water maze. Rats with radiofrequency lesions of the medial septum were required to learn which of two visible platforms in a pool of water provided a means of escape. On each of the first 4 days of training, the rats received an injection of (-)nicotine (0, 0.1 or 0.3 mg/kg, i.p.) before training. Nicotine markedly improved the performance of septal rats. This enhanced performance was maintained in rats subsequently tested 1 and 15 days later without additional drug treatment. Septal rats initially trained under nicotine were impaired, however, when the platform locations were reversed and training was conducted under saline. Our findings suggest that nicotinic receptor stimulation might be useful in the treatment of cognitive deficits.

Chronic treatment with ethanol produces supersensitivity to oxotremorine.

1. The effect of chronic treatment with ethanol (14% v:v in drinking water) on the physiological endpoint core temperature which is partially regulated by a muscarinic mechanism was measured in adult male rats (n = 8). 2. One and two weeks of treatment were associated with enhancement of the hypothermic response to oxotremorine, 0.25 mg/kg ip (p = 0.0005 and p = 0.0001, respectively). 3. The sample remained supersensitive to this muscarinic agonist 48 and 96 hours after the discontinuation of treatment (p = 0.0014 and p = 0.013 respectively). 4. Repeated injections of oxotremorine, 0.25 mg/kg ip, every other day for 10 days did not produce carry-over effects in a control experiment. 5. The results suggest that ethanol renders muscarinic mechanisms supersensitive during chronic treatment and that supersensitivity remains up to 96 hours following withdrawal.

Effects of placebo (saline) injections on core temperature in the rat.

1. Core temperature was telemetrically measured in 15 rats before (i.e., at baseline) and at 10-min intervals for 120 min following the injection of normal saline (1 ml/kg ip) or "no injection." 2. The sample exhibited a mean temperature increase of 0.60 +/- 0.10 degree C (mean +/- SEM) following injection. 3. This differed significantly from the mean increase of 0.13 +/- 0.03 degree C following "no injection" (p less than 0.001). 4. The injection of saline (1 ml/kg) affected a mean rise in core temperature of 0.55 +/- 0.07 degree C (p greater than 0.000001) in 46 animals in a second experiment. 5. These data indicate that routine handling and a simple injection comprise significant and measurable stress which must be controlled in neuropharmacological studies employing a thermoregulation paradigm.