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Biomedical subjects

Vadim Yuferov

Publications and source records attributed to Vadim Yuferov.

13 recordsLinked to original sources
PubMed2007

Effects of acute "binge" cocaine on mRNA levels of mu opioid receptor and neuropeptides in dopamine D1 or D3 receptor knockout mice.

In humans, elevations of mu opioid receptor (MOP-r) binding potential (BP) in the frontal cortex (FC) are associated with cocaine craving during early abstinence. In rats, decreases in dopaminergic (DAergic) transmission in the medial FC are associated with increased cocaine-seeking behavior. DA D1 or D3 receptor homozygous knockout (D1-/- or D3-/-) mice offer the opportunity to test the roles of these specific receptors in regulating MOP-r gene expression in response to cocaine. In the present studies, we found an increase in basal MOP-r mRNA levels in the FC of both D1-/- and D3-/- mice compared to wild type controls, with no change in the nucleus accumbens (NAc) core or caudate-putamen (CPu). Acute "binge" cocaine (3 x 15 mg/kg for 2.5 h) returned FC MOP-r mRNA levels in D1-/- or D3-/- mice to those in wild type controls. In the NAc core, the MOP-r mRNA levels after acute "binge" cocaine were decreased in D1-/- mice while increased in D3-/- mice. In the CPu, however, the MOP-r mRNA levels after acute "binge" cocaine were increased in D1-/- mice while decreased in D3-/- mice. We also found a decrease in basal orexin mRNA levels in the lateral hypothalamus of the D3-/- mice, which was unaltered by acute "binge" cocaine. Together, our findings suggest that: (1) both D1 and D3 receptors are involved in FC MOP-r gene regulation; and (2) D1 and D3 receptors play opposite roles in the effects of cocaine on MOP-r gene regulation differentially in the NAc core or CPu.

Animals↗
PubMed2006

Effects of salvinorin A, a kappa-opioid hallucinogen, on a neuroendocrine biomarker assay in nonhuman primates with high kappa-receptor homology to humans.

This study focused on the in vivo effects of the kappa-opioid hallucinogen salvinorin A, derived from the plant Salvia divinorum. The effects of salvinorin A (0.0032-0.056 mg/kg i.v.) were studied in a neuroendocrine biomarker assay of the anterior pituitary hormone prolactin in gonadally intact, adult male and female rhesus monkeys (n = 4 each). Salvinorin A produced dose- and time-dependent neuroendocrine effects, similar to the synthetic high-efficacy kappa-agonist U69,593 ((+)-(5alpha,7 alpha,8beta)-N-methyl-N-[7-(1-pyrrolidiniyl)-1-oxaspiro[4.5]dec-8yl]-benzeneacetamide), but of shorter duration than the latter. Salvinorin A was approximately equipotent to U69,593 in this endpoint (salvinorin A ED50, 0.015 mg/kg; U69,593 ED(50), 0.0098 mg/kg). The effects of i.v. salvinorin A were not prevented by a small dose of the opioid antagonist nalmefene (0.01 mg/kg s.c.) but were prevented by a larger dose of nalmefene (0.1 mg/kg); the latter nalmefene dose is sufficient to produce kappa-antagonist effects in this species. In contrast, the 5HT2 receptor antagonist ketanserin (0.1 mg/kg i.m.) did not prevent the effects of salvinorin A. As expected, the neuroendocrine effects of salvinorin A (0.0032 mg/kg i.v.) were more robust in female than in male subjects. Related studies focused on full-length cloning of the coding region of the rhesus monkey kappa-opioid receptor (OPRK1) gene and revealed a high homology of the nonhuman primate OPRK1 gene compared with the human OPRK1 gene, including particular C-terminal residues thought to be involved in receptor desensitization and internalization. The present studies indicate that the hallucinogen salvinorin A acts as a high-efficacy kappa-agonist in nonhuman primates in a translationally viable neuroendocrine biomarker assay.

Amino Acid Sequence↗
PubMed2005

Immediate withdrawal from chronic "binge" cocaine administration increases mu-opioid receptor mRNA levels in rat frontal cortex.

An increase in preprodynorphin (ppdyn) mRNA was detected in the caudate putamen of chronically cocaine-treated and 3-h withdrawn rats. An increase in mu-opioid receptor (MOP) mRNA levels was observed in the frontal cortex of 3-h withdrawn rats. Naloxone had no effect on the increase of MOP or ppdyn mRNA levels. The results indicate that the opioid system is altered during early withdrawal from chronic cocaine administration.

Animals↗
PubMed2005

Microarray studies of psychostimulant-induced changes in gene expression.

Alterations in the expression of multiple genes in many brain regions are likely to contribute to psychostimulant-induced behaviours. Microarray technology provides a powerful tool for the simultaneous interrogation of gene expression levels of a large number of genes. Several recent experimental studies, reviewed here, demonstrate the power, limitations and progress of microarray technology in the field of psychostimulant addiction. These studies vary in the paradigms of cocaine or amphetamine administration, drug doses, route and also mode of administration, duration of treatment, animal species, brain regions studied and time of tissue collection after final drug administration. The studies also utilize different microarray platforms and statistical techniques for analysis of differentially expressed genes. These variables influence substantially the results of these studies. It is clear that current microarray techniques cannot detect small changes reliably in gene expression of genes with low expression levels, including functionally significant changes in components of major neurotransmission systems such as glutamate, dopamine, opioid and GABA receptors, especially those that may occur after chronic drug administration or drug withdrawal. However, the microarray studies reviewed here showed cocaine- or amphetamine-induced alterations in the expression of numerous genes involved in the modulation of neuronal growth, cytoskeletal structures, synaptogenesis, signal transduction, apoptosis and cell metabolism. Application of laser capture microdissection and single-cell cDNA amplification may greatly enhance microarray studies of gene expression profiling. The combination of rapidly evolving microarray technology with established methods of neuroscience, molecular biology and genetics, as well as appropriate behavioural models of drug reinforcement, may provide a productive approach for delineating the neurobiological underpinnings of drug responses that lead to addiction.

Amphetamines↗
PubMed2004

Effects of extended access to high versus low cocaine doses on self-administration, cocaine-induced reinstatement and brain mRNA levels in rats.

RATIONALE: The investigation of rodent cocaine self-administration (SA) under conditions that promote escalating patterns of intake may provide insight into the loss of control over drug use that is central to human addiction. OBJECTIVE: This study examines the effects of daily long-access (LgA) SA of high or low cocaine doses on drug intake, extinction, reinstatement, and brain mRNA levels. METHODS: Three groups of male Sprague-Dawley rats were trained to self-administer cocaine during multiple-dose sessions. Short-access (ShA) rats were tested daily for multi-dose SA then remained in the chambers for 7 h with no cocaine available. LgA rats had access to low (0.5 mg/kg per infusion; LgA-LD) or high (2.0 mg/kg per infusion; LgA-HD) cocaine doses for 7 h after multi-dose SA. After 14 days, responding was extinguished, cocaine-induced reinstatement was determined, and preproenkephalin (ppENK), preprodynorphin (ppDYN), corticotropin releasing factor (CRF) and dopamine D(2) receptor (D(2)R) mRNA levels were measured in various brain regions using a quantitative solution hybridization RNase protection assay. RESULTS: Whereas SA was not altered in ShA rats and only increased during the "loading phase" in LgA-LD rats, a general escalation of intake was found in LgA-HD rats. LgA, particularly LgA-HD, rats were more susceptible to reinstatement than ShA rats. Caudate-putamen ppENK and nucleus accumbens D(2)R mRNA levels were elevated in LgA-HD rats. Overall, D(2)R mRNA levels were positively correlated with reinstatement. CONCLUSIONS: The escalation of cocaine SA under LgA conditions is dose-dependent and is associated with heightened susceptibility to drug-induced relapse. The characterization of neurobiological alterations that accompany escalated SA should facilitate the identification of mechanisms underlying the onset of human addiction.

Animals↗
PubMed2004

Redefinition of the human kappa opioid receptor gene (OPRK1) structure and association of haplotypes with opiate addiction.

The kappa opioid receptor (KOR) plays a role in stress responsivity, opiate withdrawal and responses to cocaine. KOR activation by its endogenous ligand dynorphin A(1-17) decreases basal and drug-induced striatal levels of dopamine. The complete structure of the human KOR gene (hOPRK1) has not been previously determined. This study: (i) characterized the genomic structure of the hOPRK1 gene; (ii) identified single nucleotide polymorphisms (SNPs) in the hOPRK1 gene; and (iii) investigated possible associations of these variants with vulnerability to develop heroin addiction. Analysis of 5'-RACE cDNA clones revealed the presence of a novel exon 1 ranging in length from 167 to 251 nucleotides in the 5' 5'-untranslated region of the hOPRK1 mRNA. We found that the hOPRK1 gene has four major exons and three introns, similar to rodent OPRK1 genes. Direct sequencing of amplified DNA containing all four exons and intron 1 of the hOPRK1 gene were evaluated for polymorphisms in 291 subjects (145 former heroin addicts and 146 controls). Twelve SNPs were identified, nine novel variants and three previously reported SNPs. Using logistic regression with opioid dependence as the dependent variable, the 36G>T SNP exhibited a point-wise significant association (P = 0.016) with disease status. The number of haplotypes seen in the three ethnic groups were nine, six and five for African-Americans, Caucasians, and Hispanics, respectively, with corresponding significance levels for differences in haplotype frequencies between cases and controls of P = 0.0742, 0.1015 and 0.0041. Combining ethnicities by Fisher's method yields an empirical significance level of P = 0.0020.

5' Untranslated Regions↗
PubMed2003

Differential gene expression in the rat caudate putamen after "binge" cocaine administration: advantage of triplicate microarray analysis.

Rat genome U34A (Affymetrix) oligonucleotide microarrays were used to analyze changes in gene expression in the caudate putamen (CPu) of Fischer rats induced by 1 and 3 days of "binge" cocaine (or saline) administration. A triplicate array assay of pooled RNA of each treatment group was used to evaluate the technical variability and sensitivity of microarrays. Cocaine-regulated genes were identified using the Affymetrix MAS 5.0 and Data Mining Tool v. 3. Eighty-nine upregulated and eight downregulated genes/ESTs were found after 1 day of "binge" cocaine. Following 3 days of cocaine treatment we identified 21 upregulated and 17 downregulated genes/ESTs. RNase protection assays of selected genes confirmed reliability of changes identified by the microarrays at the level of > or =1.40-fold increase. Many genes upregulated in the CPu by cocaine were immediate early genes for transcription factors and for "effector" proteins (e.g., vesl/Homer1a, Arc, synaptotagmin IV). Acute "binge" cocaine also increased mRNA levels for glutamate receptor GluR2, dopamine receptor D1, and a number of phosphatases. Genes downregulated by cocaine include several genes associated with energy metabolism in mitochondria, as well as the phosphatydylinositol-4 kinase and the regulator of G-protein signaling protein 4 (RGS4). A differential expression of somatostatin receptor SSTR2, not known to be a cocaine-responsive gene, as well as the clock gene Per2, were found by microarrays and confirmed by RNase protection assay. These results demonstrate the potential of microarrays in profiling gene expression with > or =40% increase or > or =14% decrease in mRNA levels for discovery of novel cocaine-responsive genes.

Animals↗
PubMed2003

Acute 'binge' cocaine administration elevates dynorphin mRNA in the caudate putamen of C57BL/6J but not 129/J mice.

Preprodynorphin mRNA was measured in the nucleus accumbens (NAc) and caudate putamen (CPu) after 3-day 'binge' pattern cocaine administration in C57BL/6J and 129/J mice, strains which differ in behavior and in dopamine increases in the CPu after 'binge' cocaine. In the CPu, there was increased preprodynorphin mRNA in C57BL/6J (P<0.05), but not in 129/J mice, with no differences in the NAc. Thus, 129/J mice are hyporesponsive to the preprodynorphin activating effects of acute 'binge' cocaine in the CPu.

Animals↗
PubMed2003

Quantification of multiple mRNA levels in rat brain regions using real time optical PCR.

TaqMan is significantly more sensitive than other methods of mRNA quantification and makes possible the simultaneous analysis of numerous genes in small brain regions. This technique was used to quantify levels of mRNAs of 21 genes in tissue extracts from caudate putamen and nucleus accumbens from individual rats after 1 day 'binge' cocaine or saline administration. Expression of glyceraldehyde-3-phosphate-dehydrogenase, cyclophilin and actin mRNAs as well as 18S ribosomal RNA were evaluated for normalization of levels of gene expression.

Animals↗
PubMed2003

Optimizing primer--probe design for fluorescent PCR.

TaqMan, a variation of fluorescent PCR, is a powerful tool for gene expression and polymorphism studies. Here we describe the design and evaluation of 27 new TaqMan primer-probe sets for rat genes that play a key role in neural signaling. These newly designed and synthesized probes were tested and then used for quantification of RNA isolated from rat brain. The usual length of common TaqMan probes is 25 bases or less. In these studies we constructed probes with lengths of 25-39 bases to span exon-exon junctions of nucleic acids to avoid the influence of DNA contamination upon the RNA quantification. The specific sequences at these positions required probes of these lengths to optimize hybridization. We found that the relocation of the quencher from the traditional 3' position to an internal one increases the sensitivity of probe up to 30 fold. Substitution of 6-carboxyfluorescein with Alexa Fluor 488 as fluorophore and TAMRA with non-fluorescent quencher dabcyl was also investigated. We also describe the evaluation of part of a newly designed set of 27 TaqMan primer-probes for the measurement of differences in gene expression levels in samples from the caudate putamen region of rat brain after 'binge' paradigm cocaine administration. Cocaine-induced alterations in expression of c-fos and preprodynorphin mRNAs measured by TaqMan were confirmed by ribonuclease protection assay.

Animals↗
PubMed2003

"Binge" cocaine differentially alters preproenkephalin mRNA levels in guinea pig brain.

Male Hartley guinea pigs were administered i.p. injections of cocaine or saline for 2 or 7 days in a "binge" paradigm. RNA was isolated from dissected brain regions and levels of preproenkephalin mRNA and total RNA were quantified by RNase protection assays. Following 2 days of "binge" cocaine administration, no significant alterations in preproenkephalin mRNA levels were detected in six brain regions. Following 7 days of cocaine administration, however, lower levels of preproenkephalin mRNA were observed in the nucleus accumbens and hypothalamus of cocaine-treated animals and higher levels in the frontal cortex and amygdala. These findings differed from previous studies in the rat, so an additional experiment was performed with animals treated at the 7 day time point. For increased statistical power, data from the two experiments were combined and examined by two-way ANOVAs; in this combined analysis, increases in preproenkephalin mRNA were observed in frontal cortex, amygdala, and hippocampus, decreases were found in the nucleus accumbens and hypothalamus, with no change in thalamus, caudate putamen, or cerebellum. These observed differences between guinea pigs and rats make this species an interesting model for neurobiological studies of cocaine-induced alterations in neuropeptide gene expression in the mammalian brain.

Animals↗