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E V Grigorenko

Publications and source records attributed to E V Grigorenko.

15 recordsLinked to original sources
PubMed2000

Large-scale analysis of gene expression changes during acute and chronic exposure to [Delta]9-THC in rats.

Large-scale cDNA microarrays were employed to assess transient changes in gene expression levels following acute and chronic exposure to cannabinoids in rats. A total of 24,456 cDNA clones were randomly selected from a rat brain cDNA library, amplified by PCR, and arrayed at high density to investigate differential gene expression profiles following acute (24 h), intermediate (7 days), and chronic (21 days) exposure to Delta(9)-tetrahydrocannabinol (Delta(9)-THC), the psychoactive ingredient of marijuana. Hippocampal mRNA probes labeled with (33)P obtained from both vehicle and Delta(9)-THC-treated animals were hybridized with identical cDNA microarrays. Results revealed a total of 49 different genes altered by Delta(9)-THC exposure; of these, 28 were identified, 10 had homologies to expressed sequence tags (ESTs), and 11 had no homology to known sequences in the GenBank database. Chronic or acute cannabinoid receptor activation altered expression of several genes (i.e., prostaglandin D synthase, calmodulin) involved in biochemical cascades of cannabinoid synthesis or cannabinoid effector systems. Other genes [i.e., neural cell adhesion molecule (NCAM), myelin basic protein], whose relation to cannabinoid system function was not immediately obvious, were also significantly altered. Verification of the changes obtained with the large-scale screen was determined by RNA dot blots in different groups of animals treated the same as those in the large-scale screen. Results are discussed in terms of the different types of genes affected at different times during chronic Delta(9)-THC exposure.

Animals↗
PubMed1998

Effects of long-term exposure to delta9-THC on expression of cannabinoid receptor (CB1) mRNA in different rat brain regions.

The time course of changes across 21 days of continuous exposure to Delta9-tetrahydrocannabinol (Delta9-THC) was assessed for the level of cannabinoid receptor (CB1) mRNA expression in three different rat brain regions: cerebellum, hippocampus and corpus striatum. Expression levels of CB1 mRNA were determined using semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) following a protocol which included a gene standard, 28S ribonucleic acid protein (rRNA), for normalization of levels of RNA in the three different brain regions. The levels of CB1 mRNA were assessed in four different rats at each of seven time points (6 h, and 1, 2, 3, 7, 14 and 21 days) during a 21-day Delta9-THC one dose day-1 (10 mg kg-1) treatment regimen. In the cerebellum and hippocampus, CB1 mRNA levels were increased above vehicle control animals at 7 and 14 days of treatment. In the striatum the levels of CB1 transcripts were severely reduced from days 2-14. CB1 message expression in all three brain areas returned to vehicle control levels by day 21 of Delta9-THC treatment, a time at which behavioral tolerance has been previously reported. An additional measure, receptor stimulated GTPgammaS binding, performed over the same time period revealed differential desensitization within the 3 brain areas as a function of chronic exposure to Delta9-THC. Hippocampus was the earliest to desensitize decreasing to 35% of control by treatment day 7, followed by a decrease in the cerebellum to that same level on day 14 of treatment. The striatum showed only half that degree of desensitization (65%) over the entire 21-day treatment period. Comparisons suggests that CB1 message may be regulated by different effector systems in each of the three areas during chronic Delta9-THC exposure.

Animals↗
PubMed1998

Editing status at the Q/R site of the GluR2 and GluR6 glutamate receptor subunits in the surgically excised hippocampus of patients with refractory epilepsy.

The editing status of mRNA at the Q/R site of the glutamate receptor subunits GluR2 and GluR6 modulates channel conductivity and ion selectivity of ionotropic AMPA/KA receptors. Alteration of the editing process may be involved in the debilitating effects of epilepsy. The ratio of unedited/edited (Q/R) forms of GluR2 and GluR6 subunits was examined in conjunction with the expression of two double-stranded RNA-specific adenosine deaminases (DRADA) in surgically excised hippocampus from patients with refractory epilepsy compared with that of control samples. In the majority of patients with long histories of epilepsy, the GluR2 transcript was detected in the completely edited form, however, in two (out of 16 tested) hippocampal samples of young subjects (2 and 10 years old) we were able to identify the unedited transcript of GluR2 subunit. The proportion of unedited fraction of GluR6(Q) subunit was decreased to 9% compared to control human hippocampus. We conclude that the editing process in epileptic specimens is selectively affected by seizure activity in the epileptic focus.

Adenosine Deaminase↗
PubMed1997

The presence of autoantibodies to N-terminus domain of GluR1 subunit of AMPA receptor in the blood serum of patients with epilepsy.

We have analyzed the serum from patients with refractory epilepsy for the presence of autoreactive antibodies to AMPA glutamate receptor subunits. The presence and the level of autoantibodies were assessed using immunoblot and ELISA with synthetic peptides specific for subregions of AMPA glutamate receptor subunits. Patients with refractory epilepsy exhibited strong immunoreactivity to GluR1 subunit compared to healthy donors and patients with Parkinson's disease and Alzheimer's disease. Weak immunoreactivity to other AMPA glutamate receptor subunits was also detected and the signal was diminished in the raw GluR4>GluR3>GluR2. The occurrence of autoantibodies to specific neurotransmitter subunits in the sera of patients with refractory epilepsy suggest that autoimmune process may underlie this disorder.

Autoantibodies↗
PubMed1996

Molecular and functional identification of m1 muscarinic acetylcholine receptors in rat ventricular myocytes.

The expression of muscarinic acetylcholine receptor (mAChR) subtypes in freshly isolated adult rat ventricular myocytes was investigated by reverse transcription of cellular mRNA followed by amplification of cDNA using the polymerase chain reaction (PCR). After reverse-transcriptase PCR, bands were obtained corresponding to the expected sizes for the m1 and m2 but not for the m3 to m5 mAChRs. The identity of the m1 and m2 bands was confirmed by single-cell PCR, restriction digest mapping, and Southern blot analysis. The presence of m1 and m2, but not m3, mAChR protein in these cells was shown by indirect immunofluorescence studies using subtype-specific antibodies. It was further investigated whether the identified m1 mAChR was responsible for the stimulatory effects on Ca2+ transients by high concentrations of carbachol ( > 10 mumol/L) known to occur in these cells. In pertussis toxin-treated ventricular myocytes electrically stimulated at 1 Hz, carbachol (300 mumol/L) increased the basal Ca2+ level from 96 +/- 7 to 118 +/- 8 nmol/L and the peak Ca2+ transient level from 519 +/- 32 to 640 +/- 36 nmol/L (mean +/- SEM P < .05 for both, n = 8). These effects of carbachol on Ca2+ transients were antagonized by 10 nmol/L pirenzepine, an m1 mAChR-selective antagonist. In contrast, the m2 mAChR-selective antagonist methoctramine (up to 100 nmol/L) did not inhibit the response. These results are the first to use single-cell PCR to probe cardiomyocyte-specific gene expression and indicate that m1 mAChRs are expressed on adult rat ventricular myocytes in addition to m2 mAChRs. The results further suggest that m1 mAChRs mediate the stimulatory responses on Ca2+ transients to high concentrations of cholinergic agonists seen in these cells.

Animals↗
PubMed1995

Deciphering the native GABAA receptor: is there hope?

The bewildering number of GABAA receptor subunits, their regionally dependent expression in the brain, and their supernumerary expression in single cells present major challenges in studying the function of native GABAA receptors. Which subunit combinations actually exist in native neurons? In this mini-review, GABAA receptor subunit diversity is considered in light of using the wealth of "structure-function" information gained from studying recombinant receptor to predict the subunit composition and functional properties of native GABAA receptors.

Animals↗
PubMedDate not supplied

Citrate synthase 1 interacts with the citrate transporter of yeast mitochondria.

We have previously shown that citrate synthase binds to an intrinsic protein of the mitochondrial inner membrane (D'Souza and Srere, 1983). In this paper we present evidence that this citrate synthase binding protein is the citrate transporter. We have used citrate synthase 1 mutants of Saccharomyces cerevisiae and transformants containing citrate synthase inactivated by site-directed mutagenesis to study the effect of the CS1 protein upon mitochondrial function (Kispal and Srere). In the present study citrate uptake and oxidation were measured during state 3 conditions (presence of 200 microM ADP) in the mitochondria of several strains of Saccharomyces cerevesiae: a parental strain containing wild-type mitochondrial citrate synthase (CS1) and strains derived from a CS1 deficient strain in which the CS1 gene was disrupted by insertion of the LEU2 gene. These strains were generated from the CS1- cells by transformation with vectors encoding site-specific mutants of CS1 possessing very low levels of enzymatic activity. One such strain in this study was subsequently found to have undergone reversion to produce a strain which had activity very similar to wild type. Positive correlation between citrate uptake and the rate of citrate oxidation was found, suggesting coupling of the two processes. Both mitochondrial citrate uptake and oxidation were decreased in the mutant lacking any form of CS1 protein. Reintroduction of mutagenized CS1 into yeast causes an enhancement in the rate of state 3 oxygen consumption and of citrate uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Carrier Proteins↗
PubMedDate not supplied

Expression profiling of GABAA receptor beta-subunits in the rat retina.

This study profiled the expression of the family of GABAA receptor beta-subunits in the adult rat retina. Using a combination of reverse transcriptase reaction followed by polymerase chain reaction (RT-PCR) with gene-specific primers, the expression of mRNAs encoding the beta 1, beta 2, and beta 3 subunits was first examined in the intact retina and then in separated retinal nuclear layers. However, it was found that a critical analysis had to be carried out at the level of the single cell in order to resolve the differential patterns of expression among the retinal cell types. When cells were isolated and identified following acute dissociation, RT-PCR revealed that individual rod photoreceptor cells expressed consistently the beta 1 and beta 2 messages while the bipolar cells expressed the beta 1 and beta 3 messages. Ganglion cells displayed considerable variability in beta-subunit expression, perhaps reflecting their functional and morphological heterogeneity in the retina. In contrast, the nonneuronal Mueller cells did not express any of the beta-subunit messages. These results indicate that the expression of GABAA receptor subunits is cell-type dependent. Furthermore, as the expression of other families of GABAA receptor subunits are profiled and the patterns of subunit assembly are better understood, our results raise the possibility that GABAA receptors with different subunit compositions can be expected to be coexpressed within a single retinal neuron.

Animals↗
PubMedDate not supplied

Correlation between a bicuculline-resistant response to GABA and GABAA receptor rho 1 subunit expression in single rat retinal bipolar cells.

Using patch-clamp recording in combination with reverse transcriptase-polymerase chain reaction (RT-PCR), we show in individual bipolar cells acutely dissociated from the adult rat retina a correlation between the expression of the GABAA receptor rho 1 subunit mRNA and a bicuculline-resistant, diazepam-insensitive component of the GABA-activated whole-cell current response. This "GABAC-like" response, contributing to approximately 42% of the GABA-activated whole-cell current and displaying variable sensitivity to picrotoxin, was found in bipolar cells but not in any of the ganglion cells examined. Expression profiling of GABAA receptor subunit mRNAs in individual electrophysiologically tested retinal neurons revealed that, while both bipolar cells and ganglion cells may express numerous GABAA receptor subunit isoforms, including that of rho 2, the expression of the rho 1 subunit was strictly limited to bipolar cells. We propose a possible link between the presence of a receptor with GABAC-like pharmacological profile and the expression of the retina-specific rho 1 subunit isoform. The results presented in this study constitute the first direct demonstration of such a correlation at the single-cell level.

Animals↗
PubMedDate not supplied

[Effect of light negative hydroaeroions on electromagnetic coupling of frog Rana ridibunda auricle].

It is shown that negative hydroaeroions cause a decrease of the systole strength of freshly prepared auricle and activation of the tired auricle; a decrease of the amplitude and length of the heart trabecula action potentials due to depression of slow input Ca2+ current; shift of the threshold of activation of fast input Na+ current to low potentials; partly elimination of the rise of the auricle systole strength under novodrine. The latter effects were not observed under atropine and indomethacin.

Action Potentials↗
PubMedDate not supplied

[Effect of negative hydro-aero ions on the structure and functional properties of mitochondria].

Studies were carried out of the physical mechanism of biological effect of natural stimulant of the living activity--light negative hydroaeroions. The latter are a hydroxyl separated from water ions and designated here as electrically noncompensated hydroxyl OH-. Unique effect of OH-, i.e. fast restoration and prevention of fine damage of native mitochondria (NM) at storage was revealed on mitochondria preparations by specific procedure, providing preservation of the ability of self-organization--formation of aggregated and denser packing--native mitochondria. This effect of OH- is conditioned by increased formation of native mitochondria aggregates and is concerned with better ADP phosphorylation and Ca2- release. The effect of the air current OH- is produced by water action presaturated with OH-. OH- induces in water cooperative structure formation preserved for many days, which is indicated by an increase of its heat capacity and decrease of surface tension. The principal factor in OH- effect both on mitochondria and water seems to be a decrease of local positive changes. It is of more advantage in NM water suspensions to order (structurate) NM with disordering water, which explains formation of NM stable aggregates. OH- effect supports the main function of the organism struggling with proton excess which destroys biological self-organization. Strengthened structural self-organization under the effect of OH- found in NM seems to be of universal importance for biological macromolecules and membranes and is a primary effect of OH- on the living objects.

Animals↗
PubMedDate not supplied

[Substrate inhibition in the tricarboxylic acid cycle].

It has been shown in the experiments on rat liver mitochondria under glucose hexo-kinase load that excess of substrates of (1-20 mM) pyruvate, acetate, propionate, pent-4-enoate and malate may induce oxidation of NAD(P)H and inhibition of mitochondrial respiration (by 20-50% and more) due to a decreased rate of hydrogen production by tricarboxylic acid cycle. It has been concluded from the analysis of mathematical models and metabolite-testings which remove this inhibition that for pyruvate and acetate this inhibition is an autocatalytic one. It is related to a decreased level of CoA and oxaloacetate due to the formation of "traps" such as acetyl-CoA and alpha-kotoglutarate. For propionate and pent-4-enoate in the bicarbonate-free medium suppression of the flux in the cycle is concerned with a decreased level of CoA, acetyl-CoA and succionoyl CoA due to the accumulation of propionyl-CoA. It seems to be also concerned with the inhibition of citrate-synthetase and alpha-ketoglutarate-dehydrogenase by propionyl-CoA. Malate (in the presence of malonate) can inhibit respiration at the expense of direct inhibition of citrate-synthetase.

Acetates↗
PubMedDate not supplied

[Effect of aeroions on the relationship between direct and reversed electron transfer in mitochondria under stress].

Opposite changes of direct (respiration) and reversed (from succinate on pyridin nucleotides) energy dependent electron transfer was revealed in rat liver mitochondria under stress. An increase of respiration using added and especially endogenous succinate is observed with corresponding acceleration of phosphorylation. The reversed electron transfer is weaker. This interconversion of the electron flow occurs without the coupling loss and represents a physiological control of the relationship between the external work of mitochondria (ATP synthesis and ion transport) being realized at the expense of direct electron transfer and regenerative synthetic processes with the use of protons supplied by reversed electron transfer. The influence of aeroions on animal after stress resulted in a decrease of the changes described, restricting the excess of direct electron transfer and elevating reductive reactions of reversed electron transfer.

Adenosine Triphosphate↗