Selective inhibition of dopamine-beta-hydroxylase enhances dopamine release from noradrenergic terminals in the medial prefrontal cortex. 2015

Paola Devoto, and Giovanna Flore, and Pierluigi Saba, and Roberto Frau, and Gian L Gessa
Department of Biomedical Sciences Section of Neuroscience and Clinical Pharmacology University of Cagliari Cagliari Italy ; "Guy Everett Laboratory" University of Cagliari Cagliari Italy ; Center of Excellence "Neurobiology of Addiction" University of Cagliari Cagliari Italy.

BACKGROUND Disulfiram has been claimed to be useful in cocaine addiction therapy, its efficacy being attributed to dopamine-beta-hydroxylase (DBH) inhibition. Our previous results indicate that disulfiram and the selective DBH inhibitor nepicastat increase extracellular dopamine (DA) in the rat medial prefrontal cortex (mPFC), and markedly potentiated cocaine-induced increase. Concomitantly, in rats with cocaine self-administration history, cocaine-seeking behavior induced by drug priming was prevented, probably through overstimulation of D1 receptors due to the DA increase. The present research was aimed at studying the neurochemical mechanisms originating the enhanced DA release. METHODS Noradrenergic system ablation was attained by intracerebroventricular (i.c.v.) administration of the neurotoxin anti-DBH-saporin (aDBH-sap). DA, noradrenaline (NA), and DOPAC were assessed by HPLC after ex vivo tissue extraction or in vivo microdialysis. Control and denervated rats were subjected to microdialysis in the mPFC and caudate nucleus to evaluate the effect of nepicastat-cocaine combination on extracellular DA levels and their regulation by α2-adrenoceptors. RESULTS Fifteen days after neurotoxin or its vehicle administration, tissue and extracellular NA were reduced to less than 2% the control value, while extracellular DA was increased by approximately 100%. In control rats, nepicastat given alone and in combination with cocaine increased extracellular DA by about 250% and 1100%, respectively. In denervated rats, nepicastat slightly affected extracellular DA, while in combination with cocaine increased extracellular DA by 250%. No differences were found in the caudate nucleus. Clonidine almost totally reversed the extracellular DA elevation produced by nepicastat-cocaine combination, while it was ineffective in denervated rats. CONCLUSIONS This research shows that the increase of extracellular DA produced by nepicastat alone or in combination with cocaine was prevented by noradrenergic denervation. The results indicate that nepicastat enhances DA release from noradrenergic terminals supposedly by removing NA from α2-autoreceptors. In addition to the inhibition of DA uptake, the latter mechanism may explain the synergistic effect of cocaine on nepicastat-induced DA release.

UI MeSH Term Description Entries
D007093 Imidazoles Compounds containing 1,3-diazole, a five membered aromatic ring containing two nitrogen atoms separated by one of the carbons. Chemically reduced ones include IMIDAZOLINES and IMIDAZOLIDINES. Distinguish from 1,2-diazole (PYRAZOLES).
D007276 Injections, Intraventricular Injections into the cerebral ventricles. Intraventricular Injections,Injection, Intraventricular,Intraventricular Injection
D008297 Male Males
D009638 Norepinephrine Precursor of epinephrine that is secreted by the ADRENAL MEDULLA and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers, and of the diffuse projection system in the brain that arises from the LOCUS CERULEUS. It is also found in plants and is used pharmacologically as a sympathomimetic. Levarterenol,Levonorepinephrine,Noradrenaline,Arterenol,Levonor,Levophed,Levophed Bitartrate,Noradrenaline Bitartrate,Noradrénaline tartrate renaudin,Norepinephrin d-Tartrate (1:1),Norepinephrine Bitartrate,Norepinephrine Hydrochloride,Norepinephrine Hydrochloride, (+)-Isomer,Norepinephrine Hydrochloride, (+,-)-Isomer,Norepinephrine d-Tartrate (1:1),Norepinephrine l-Tartrate (1:1),Norepinephrine l-Tartrate (1:1), (+,-)-Isomer,Norepinephrine l-Tartrate (1:1), Monohydrate,Norepinephrine l-Tartrate (1:1), Monohydrate, (+)-Isomer,Norepinephrine l-Tartrate (1:2),Norepinephrine l-Tartrate, (+)-Isomer,Norepinephrine, (+)-Isomer,Norepinephrine, (+,-)-Isomer
D003042 Cocaine An alkaloid ester extracted from the leaves of plants including coca. It is a local anesthetic and vasoconstrictor and is clinically used for that purpose, particularly in the eye, ear, nose, and throat. It also has powerful central nervous system effects similar to the amphetamines and is a drug of abuse. Cocaine, like amphetamines, acts by multiple mechanisms on brain catecholaminergic neurons; the mechanism of its reinforcing effects is thought to involve inhibition of dopamine uptake. Cocaine HCl,Cocaine Hydrochloride,HCl, Cocaine,Hydrochloride, Cocaine
D004298 Dopamine One of the catecholamine NEUROTRANSMITTERS in the brain. It is derived from TYROSINE and is the precursor to NOREPINEPHRINE and EPINEPHRINE. Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement. A family of receptors (RECEPTORS, DOPAMINE) mediate its action. Hydroxytyramine,3,4-Dihydroxyphenethylamine,4-(2-Aminoethyl)-1,2-benzenediol,Dopamine Hydrochloride,Intropin,3,4 Dihydroxyphenethylamine,Hydrochloride, Dopamine
D004299 Dopamine beta-Hydroxylase Dopamine beta-Monooxygenase,Dopamine beta Hydroxylase,Dopamine beta Monooxygenase,beta-Hydroxylase, Dopamine,beta-Monooxygenase, Dopamine
D004791 Enzyme Inhibitors Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction. Enzyme Inhibitor,Inhibitor, Enzyme,Inhibitors, Enzyme
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D012646 Self Administration Administration of a drug or chemical by the individual under the direction of a physician. It includes administration clinically or experimentally, by human or animal. Administration, Self,Administrations, Self,Self Administrations

Related Publications

Paola Devoto, and Giovanna Flore, and Pierluigi Saba, and Roberto Frau, and Gian L Gessa
May 2018, Behavioural brain research,
Paola Devoto, and Giovanna Flore, and Pierluigi Saba, and Roberto Frau, and Gian L Gessa
May 2016, Proceedings of the National Academy of Sciences of the United States of America,
Paola Devoto, and Giovanna Flore, and Pierluigi Saba, and Roberto Frau, and Gian L Gessa
April 1989, The Journal of comparative neurology,
Paola Devoto, and Giovanna Flore, and Pierluigi Saba, and Roberto Frau, and Gian L Gessa
December 1996, European journal of pharmacology,
Paola Devoto, and Giovanna Flore, and Pierluigi Saba, and Roberto Frau, and Gian L Gessa
January 1990, Annals of the New York Academy of Sciences,
Paola Devoto, and Giovanna Flore, and Pierluigi Saba, and Roberto Frau, and Gian L Gessa
August 1996, The Journal of pharmacology and experimental therapeutics,
Paola Devoto, and Giovanna Flore, and Pierluigi Saba, and Roberto Frau, and Gian L Gessa
March 2017, Physiological reports,
Paola Devoto, and Giovanna Flore, and Pierluigi Saba, and Roberto Frau, and Gian L Gessa
January 2001, Brain research,
Paola Devoto, and Giovanna Flore, and Pierluigi Saba, and Roberto Frau, and Gian L Gessa
November 1990, European journal of pharmacology,
Copied contents to your clipboard!