Genetic Targeting in Cerebellar Purkinje Cells: an Update

Since the last review paper published in Cerebellum in 2002 [1], there has been a substantial increase in the number of experiments utilizing transgenic manipulations in murine cerebellar Purkinje cells. Most of these approaches were made possible with the use of the Cre/loxP methodology and pcp2/L7 based Cre recombinase expressing transgenic mouse strains. This review aims to summarize all studies which used Purkinje cell specific transgenesis since the first use of mouse strain with Purkinje cell specific Cre expression in 2002

Extended neuroleptic administration modulates NMDA-R subunit immunoexpression in the rat neocortex and diencephalon

Background This study aimed to evaluate the effect of extended olanzapine, clozapine and haloperidol administration on NMDA-R subunit immunoexpression in the rat neocortex and diencephalon. Methods To explore NR1, NR2A and NR2B subunit protein expression, densytometric analysis of immunohistochemically stained brain slices was performed. Results Interestingly, all neuroleptics caused a downregulation of NMDA-R subunit expression in the thalamus but increased the level of NR1 in the hypothalamus. Olanzapine upregulated hypothalamic NR2A expression, while clozapine and haloperidol decreased hypothalamic levels. We observed no significant changes in NR2B immunoreactivity. None of the studied medications had significant influence on NMDA-R subunit expression in the neocortex. Conclusions Neuroleptic-induced reduction in the expression of thalamic NMDA-R subunits may play an important role in the regulation of glutamatergic transmission disorders in cortico–striato–thalamo–cortical loop in schizophrenia. A decrease in NMDA signaling in this region after long-term neuroleptic administration may also cautiously explain the incomplete effectiveness of these drugs in the therapy of schizophrenia-related cognitive disturbances

Cytochrome P450 mRNA expressions along with in vitro differentiation of hepatocyte precursor cells from fetal, young and old rats.

Non-differentiated cells are attractive targets for cell therapy. During liver regeneration oval cells intensively proliferate and differentiate extending their metabolic activity. Hepatic cytochromes P450 (CYPs) can be linked either with metabolic activation of toxic compounds or drug metabolism. We investigated the differentiation and biotransformative potential of non-differentiated cells in primary cell cultures isolated from livers of fetuses (16-days-old), young (4-months-old) and old (20-months-old) rats. Under the conditions of experimental hepatocarcinogenesis, adult rats were fed for three weeks with CDE diet. Liver cells were cultured and precursor cells were differentiated to hepatocytes following induction with sodium butyrate (SB) or dimethyl sulphoxide (DMSO) in culture on MesenCult medium. We identified a number of cells expressing Thy-1, CD34, alpha-fetoprotein, cytokeratines--CK18 or CK19 and glutathione transferases--GSTpi or GSTalpha. In vitro differentiation of these cells, isolated from CDE-treated rats begun earlier as compared to non-treated ones. Age-dependent changes in the cell differentiation sequence, as well as CYPmRNA expression sequence accompanying precursor cells differentiation, were also observed. mRNA expression of CYP1A2, CYP2B1/2 and CYP3A1 was higher in the cells of young rats, but in the case of CYP2E1--in the cells of old rats. It was concluded that both proliferation and differentiation potential of oval cells, decreased with age

Expression of cytochrome CYP2B1/2 in nonpregnant, pregnant and fetal rats exposed to tobacco smoke.

Four-month-old female Wistar rats were exposed for 20 days to tobacco smoke obtained from non-filter cigarettes. During the exposure, concentration of tobacco smoke was monitored indirectly by measuring the CO level (1500 mg/m3 air). The efficacy of exposure was assessed by measuring urine nicotine and cotinine levels. Cigarette smoke did not change total cytochrome P450 and b5 protein levels in any of the organs studied, and most of these organs did not show any changes in the activity of reductases associated with these cytochromes. Following exposure to tobacco smoke, fetal rat liver expressed CYP2B1/2 protein; in newborns (day 1) both liver and lung showed CYP2B1/2 protein expression and very low pentoxyresorufin O-dealkylase activity. Western blot analysis of adult liver, lung, heart, but not of brain microsomes, showed that tobacco smoke induced CYP2B1/2 in both nonpregnant and pregnant rats, though its expression was lower in the livers and hearts of pregnant females. In the rat and human placenta, neither rat CYP2B1/2 nor human CYP2B6 showed basal or tobacco smoke-induced expression at the protein level. This study shows clearly that the expression of CYP2B1/2, which metabolizes nicotine and some drugs and activates carcinogens, is controlled in rats by age-, pregnancy-, and tissue-specific regulatory mechanisms

Effect of pyrantel and dimethoate administration on rat liver cytochrome P450 system

The cytochrome P450 system in rat liver after administration of dimethoate (5 d, 1/10 DL50), pyrantel embonate (3 d, 1/5 DL50) or both xenobiotics simultaneously was analysed. Both compounds were administered directly to the stomach by the tube and the components of cytochrome P450 system were analysed in the microsomal fraction of the liver up to 14 d after the last applied dose. Intoxication with pyrantel diminished the total content of cytochrome P450 in all analysed time intervals. On the other hand, intoxication with dimethoate resulted in increase in the cytochrome P450 content 2 d after the last applied dose. The changes in activities of NADPH: cyt.P450 and NADH: cyt.b5 reductases were small and statistically not significant. Both dimethoate and pyrantel affected the expression of CYP1A2, CYP2B1/2 and CYP3A1 proteins. Both compounds had a slight negative effect on CYP2B1/2. In animals receiving dimethoate as well as both xenobiotics simultaneously a significant increase in the level of CYP1A2 protein was observed. However, stimulatory effect of dimethoate on the expression of CYP1A2 was abolished by simultaneous intoxication with pyrantel. The changes in CYP3A1 protein expression corresponded with those observed for the total amount of cytochrome P450.</p