Biomaterial Database

Differences in the opioid system in selected brain regions of alcohol-preferring and alcohol-nonpreferring rats. 1999

P Fadda, and S Tronci, and G Colombo, and W Fratta

Department of Neuroscience, University of Cagliari, Italy. pfadda@unica.it

BACKGROUND Previous studies have suggested that alcohol-reinforcing effects are mediated by the endogenous opioid system, which, in turn, stimulates mesolimbic dopaminergic neurotransmission. In addition, evidence obtained in both humans and rats indicates that genetic factors may influence alcohol-drinking behavior. In the present study, we examined several components of the opioid system in selected brain regions of rats bred selectively for their innate alcohol preference (Sardinian preferring = sP) or alcohol aversion (Sardinian nonpreferring = sNP). METHODS To evaluate whether differences observed were consequent to alcohol intake, sP rats were divided into two subgroups, ethanol-naive sP (sP) and ethanol-experienced sP (sPexp). Opioid receptors were labeled, using [3H]naloxone (mu, delta, and kappa receptors), [D-Ala2,N-Me-Phe4,Gly,ol5]enkephalin ([3H]DAMGO; mu receptors), and [D-Ala2,D-Leu5]enkephalin ([3H]DADLE; delta receptors), by means of quantitative autoradiography. Enkephalin and dynorphin mRNA contents were measured by in situ hybridization by using 25- and 47-base oligonucleotide probes with sequences complementary to mRNA encoding rat enkephalin or dynorphin. RESULTS Our results revealed a significant reduction of opioid receptors in caudate-putamen nucleus and in the shell portion of the nucleus accumbens in sP compared with sNP rats. Alcohol intake partially reversed this reduction in the caudate-putamen nucleus. In addition, enkephalin mRNA expression was found to be decreased in the ventral part of caudate-putamen nucleus and increased in the cerebral cortex of sP rats compared with sNP rats; no significant differences were found in dynorphin mRNA expression in any of the brain areas examined. CONCLUSIONS Differences observed between the two lines of rats may implicate that genetic modifications in the opioid system are possibly responsible for the innate preference of sP rats toward alcohol intake. At the same time, it cannot be excluded that other functions might also be affected to some degree.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009270	Naloxone	A specific opiate antagonist that has no agonist activity. It is a competitive antagonist at mu, delta, and kappa opioid receptors.	MRZ 2593-Br,MRZ-2593,Nalone,Naloxon Curamed,Naloxon-Ratiopharm,Naloxone Abello,Naloxone Hydrobromide,Naloxone Hydrochloride,Naloxone Hydrochloride Dihydride,Naloxone Hydrochloride, (5 beta,9 alpha,13 alpha,14 alpha)-Isomer,Naloxone, (5 beta,9 alpha,13 alpha,14 alpha)-Isomer,Narcan,Narcanti,Abello, Naloxone,Curamed, Naloxon,Dihydride, Naloxone Hydrochloride,Hydrobromide, Naloxone,Hydrochloride Dihydride, Naloxone,Hydrochloride, Naloxone,MRZ 2593,MRZ 2593 Br,MRZ 2593Br,MRZ2593,Naloxon Ratiopharm
D009292	Narcotic Antagonists	Agents inhibiting the effect of narcotics on the central nervous system.	Competitive Opioid Antagonist,Narcotic Antagonist,Opioid Antagonist,Opioid Antagonists,Opioid Receptor Antagonist,Opioid Reversal Agent,Competitive Opioid Antagonists,Opioid Receptor Antagonists,Opioid Reversal Agents,Agent, Opioid Reversal,Agents, Opioid Reversal,Antagonist, Competitive Opioid,Antagonist, Narcotic,Antagonist, Opioid,Antagonist, Opioid Receptor,Antagonists, Competitive Opioid,Antagonists, Narcotic,Antagonists, Opioid,Antagonists, Opioid Receptor,Opioid Antagonist, Competitive,Opioid Antagonists, Competitive,Receptor Antagonist, Opioid,Receptor Antagonists, Opioid,Reversal Agent, Opioid,Reversal Agents, Opioid
D011957	Receptors, Opioid	Cell membrane proteins that bind opioids and trigger intracellular changes which influence the behavior of cells. The endogenous ligands for opioid receptors in mammals include three families of peptides, the enkephalins, endorphins, and dynorphins. The receptor classes include mu, delta, and kappa receptors. Sigma receptors bind several psychoactive substances, including certain opioids, but their endogenous ligands are not known.	Endorphin Receptors,Enkephalin Receptors,Narcotic Receptors,Opioid Receptors,Receptors, Endorphin,Receptors, Enkephalin,Receptors, Narcotic,Receptors, Opiate,Endorphin Receptor,Enkephalin Receptor,Normorphine Receptors,Opiate Receptor,Opiate Receptors,Opioid Receptor,Receptors, Normorphine,Receptors, beta-Endorphin,beta-Endorphin Receptor,Receptor, Endorphin,Receptor, Enkephalin,Receptor, Opiate,Receptor, Opioid,Receptor, beta-Endorphin,Receptors, beta Endorphin,beta Endorphin Receptor,beta-Endorphin Receptors
D001931	Brain Mapping	Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.	Brain Electrical Activity Mapping,Functional Cerebral Localization,Topographic Brain Mapping,Brain Mapping, Topographic,Functional Cerebral Localizations,Mapping, Brain,Mapping, Topographic Brain
D001947	Breeding	The production of offspring by selective mating or HYBRIDIZATION, GENETIC in animals or plants.	Breedings
D004745	Enkephalins	One of the three major families of endogenous opioid peptides. The enkephalins are pentapeptides that are widespread in the central and peripheral nervous systems and in the adrenal medulla.	Enkephalin
D005819	Genetic Markers	A phenotypically recognizable genetic trait which can be used to identify a genetic locus, a linkage group, or a recombination event.	Chromosome Markers,DNA Markers,Markers, DNA,Markers, Genetic,Genetic Marker,Marker, Genetic,Chromosome Marker,DNA Marker,Marker, Chromosome,Marker, DNA,Markers, Chromosome
D000437	Alcoholism	A primary, chronic disease with genetic, psychosocial, and environmental factors influencing its development and manifestations. The disease is often progressive and fatal. It is characterized by impaired control over drinking, preoccupation with the drug alcohol, use of alcohol despite adverse consequences, and distortions in thinking, most notably denial. Each of these symptoms may be continuous or periodic. (Morse & Flavin for the Joint Commission of the National Council on Alcoholism and Drug Dependence and the American Society of Addiction Medicine to Study the Definition and Criteria for the Diagnosis of Alcoholism: in JAMA 1992;268:1012-4)	Alcohol Abuse,Alcoholic Intoxication, Chronic,Ethanol Abuse,Alcohol Addiction,Alcohol Dependence,Alcohol Use Disorder,Abuse, Alcohol,Abuse, Ethanol,Addiction, Alcohol,Alcohol Use Disorders,Chronic Alcoholic Intoxication,Dependence, Alcohol,Intoxication, Chronic Alcoholic,Use Disorders, Alcohol
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