Dataset Information

Abuse-Related Neurochemical Effects of Para-Substituted Methcathinone Analogs in Rats: Microdialysis Studies of Nucleus Accumbens Dopamine and Serotonin.

ABSTRACT: Methcathinone (MCAT) is a monoamine releaser and parent compound to a new class of designer drugs that includes the synthetic cathinones mephedrone and flephedrone. Using MCAT and a series of para-substituted (or 4-substituted) MCAT analogs, it has been previously shown that expression of abuse-related behavioral effects in rats correlates both with the volume of the para substituent and in vitro neurochemical selectivity to promote monoamine release via the dopamine (DA) versus serotonin (5-HT) transporters in rat brain synaptosomes. The present study used in vivo microdialysis to determine the relationship between these previous measures and the in vivo neurochemical selectivity of these compounds to alter nucleus accumbens (NAc) DA and 5-HT levels. Male Sprague-Dawley rats were implanted with bilateral guide cannulae targeting the NAc. MCAT and five para-substituted analogs (4-F, 4-Cl, 4-Br, 4-CH3, and 4-OCH3) produced dose- and time-dependent increases in NAc DA and/or 5-HT levels. Selectivity was determined as the dose required to increase peak 5-HT levels by 250% divided by the dose required to increase peak DA levels by 250%. This measure of in vivo neurochemical selectivity varied across compounds and correlated with 1) in vivo expression of abuse-related behavioral effects (r = 0.89, P = 0.02); 2) in vitro selectivity to promote monoamine release via DA and 5-HT transporters (r = 0.95, P < 0.01); and 3) molecular volume of the para substituent (r = -0.85, P = 0.03). These results support a relationship between these molecular, neurochemical, and behavioral measures and support a role for molecular structure as a determinant of abuse-related neurochemical and behavioral effects of MCAT analogs.

SUBMITTER: Suyama JA

PROVIDER: S-EPMC4702071 | biostudies-literature | 2016 Jan

REPOSITORIES: biostudies-literature

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Abuse-Related Neurochemical Effects of Para-Substituted Methcathinone Analogs in Rats: Microdialysis Studies of Nucleus Accumbens Dopamine and Serotonin.

Suyama Julie A JA Sakloth Farhana F Kolanos Renata R Glennon Richard A RA Lazenka Matthew F MF Negus S Stevens SS Banks Matthew L ML

The Journal of pharmacology and experimental therapeutics 20151015 1

Methcathinone (MCAT) is a monoamine releaser and parent compound to a new class of designer drugs that includes the synthetic cathinones mephedrone and flephedrone. Using MCAT and a series of para-substituted (or 4-substituted) MCAT analogs, it has been previously shown that expression of abuse-related behavioral effects in rats correlates both with the volume of the para substituent and in vitro neurochemical selectivity to promote monoamine release via the dopamine (DA) versus serotonin (5-HT) ...[more]

PMID: 26645638

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Project description:RationaleNovel synthetic "bath salt" cathinones continue to appear on the street as abused and addictive drugs. The range of subjective experiences produced by different cathinones suggests that some compounds have primarily dopaminergic activity (possible stimulants) while others have primarily serotonergic activity (possible empathogenics). An understanding of the structure activity relationships (SARs) of these compounds will help in assessing the likely behavioral effects of future novel structures, and to define potential therapeutic strategies to reverse any reinforcing effects.ObjectivesA series of methcathinone analogs was systematically studied for their activity at the dopamine and serotonin transporters. Compound structures varied at the aromatic group, either by substituent or by replacement of the phenyl ring with a naphthalene or indole ring.MethodsA novel, high-yielding synthesis of methcathinone hydrochlorides was developed which avoids isolation of the unstable free bases. Neurotransmitter transporter release activity was determined in rat brain synaptosomes as previously reported. Compounds were also screened for activity at the norepinephrine transporter.ResultsTwenty-eight methcathinone analogs were analyzed and fully characterized in dopamine and serotonin transporter release assays. Compounds substituted at the 2-position (ortho) were primarily dopaminergic. Compounds substituted at the 3-position (meta) were found to be much less dopaminergic, with some substituents favoring serotonergic activity. Compounds substituted at the 4-position (para) were found to be far more serotonergic, as were disubstituted compounds and other large aromatic groups. One exception was the fluoro-substituted analogs which seem to favor the dopamine transporter.ConclusionsThe dopaminergic to serotonergic ratio can be manipulated by choice of substituent and location on the aromatic ring. It is therefore likely possible to tweak the subjective and reinforcing effects of these compounds by adjusting their structure. Certain substituents like a fluoro group tend to favor the dopamine transporter, while others like a trifluoromethyl group favor the serotonin transporter.

Project description:Background: The incidence of alcohol and tobacco co-abuse is as high as 80%. The molecular mechanism underlying this comorbidity is virtually unknown but interactions between these drugs have important implications for the development of, and recovery from drug dependence. Methods: We investigated the effects of chronic tobacco and alcohol abuse and the interaction of the two behaviours on global gene expression in the human nucleus accumbens using cDNA microarrays and 20 alcoholic and control cases, with and without smoking comorbidity. Changes in gene expression were established by two-way ANOVA. Unsupervised hierarchical clustering was utilized to probe the strength of the data sets. Results: Subjecting the data sets derived from microarray gene expression screening to unsupervised hierarchical clustering tied the cases into distinct groups. When considering all alcohol-responsive genes, alcoholics were separated from non alcoholics with the exception of one control case. All smokers were distinguished from non smokers based on similarity in expression of smoking-sensitive genes. In the nucleus accumbens, alcohol-responsive genes were associated with transcription, lipid metabolism and signalling. Smoking-sensitive genes were predominantly assigned to functional groups concerned with RNA processing and the endoplasmic reticulum. Both drugs influenced the expression of genes involved in matrix remodelling, proliferation and cell morphogenesis. Additionally, a gene set encoding proteins involved in the canonical pathway ‘regulation of the actin cytoskeleton’ was induced in response to alcohol and tobacco co-abuse and included. Conclusions: The region-specific modulation of alcohol-sensitive gene expression by smoking may have important consequences for alcohol-induced aberrations within the mesolimbic dopaminergic system. The data set contained individual RNA samples extracted from the nucleus accumbens from 5 non smoking non drinking control case, 5 non smoking alcoholics, 5 non drinking smokers, and 5 smoking alcoholics. An aliquot if each sample was combined to generate a reference pool. Each sample was amplified individually and labelled with Cy3 in the process, the reference samples was amplified and labelled with Cy5. Each sample was hybridised competitively against the reference sample to 1 array.

Dataset Information

Abuse-Related Neurochemical Effects of Para-Substituted Methcathinone Analogs in Rats: Microdialysis Studies of Nucleus Accumbens Dopamine and Serotonin.

Publications

Abuse-Related Neurochemical Effects of Para-Substituted Methcathinone Analogs in Rats: Microdialysis Studies of Nucleus Accumbens Dopamine and Serotonin.

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