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Monoaminergic Systems (monoaminergic + system)
Selected AbstractsInfluence of metyrapone treatment during pregnancy on the development and maturation of brain monoaminergic systems in the ratACTA PHYSIOLOGICA, Issue 4 2009M. L. Leret Abstract Aim:, This study examines the effect of reducing the corticosterone levels of gestating rat dams on the postnatal development and maturation of monoaminergic systems in their offspring's brains. Methods:, Metyrapone, an inhibitor of CORT synthesis, was administered to pregnant rats from E0 to E17 of gestation. Monoamine concentrations were determined in male and female offspring at postnatal days (PN) 23 and 90 in the hippocampus, hypothalamus and striatum. Results:, Reducing maternal corticosterone (mCORT) during gestation led to alterations in dopamine and serotonin levels in all three brain areas studied at PN 23. Alterations persisted until at least PN 90 in the serotonergic systems; the dopamine content of the hippocampus also remained modified. Reduced mCORT during gestation also led to alterations in the development and maturation of the hypothalamic noradrenergic systems. Sexually dimorphic responses were observed in all these monoaminergic systems at different times. Conclusion:, These results suggest that while they are still developing, brain monoaminergic systems are particularly sensitive to epigenetic influences. An adequate foetal level of CORT is required for the normal ontogeny of brain monoaminergic systems. The present data also provide that during the critical period of brain development, maternal CORT plays an important role in the sexual differentiation of monoaminergic systems, with particular influence on brain serotonergic neurones. [source] RESEARCH FOCUS ON COMPULSIVE BEHAVIOUR IN ANIMALS: Compulsive alcohol drinking in rodentsADDICTION BIOLOGY, Issue 4 2009Valentina Vengeliene ABSTRACT Upon prolonged alcohol exposure, the behaviour of an individual can gradually switch from controlled to compulsive. Our review is focused on the neurobiological mechanisms that might underlie this transition as well as the factors that are influencing it. Animal studies suggest that temporally increased alcohol consumption during post-abstinence drinking is accompanied by a loss of flexibility of the behaviour and therefore, could serve as a model for compulsive alcohol drinking. However, studies using different alcohol-preferring rat lines in the post-abstinence drinking model suggest that high alcohol consumption does not necessarily lead to the development of compulsive drinking. This indicates the significance of genetic predisposition to compulsive behaviour. Neuroimaging data show that chronic alcohol consumption affects the activity of several brain regions such as the extrapyramidal motor system and several areas of the prefrontal cortex including the orbitofrontal and anterior cingulate cortex. Similar changes in brain activity is seen in patients suffering from obsessive,compulsive disorder at baseline conditions and during provocation of obsessive thoughts and urge to perform compulsive-like rituals. This indicates that dysfunction of these regions may be responsible for the expression of compulsive components of alcohol drinking behaviour. Several brain neurotransmitter systems seem to be responsible for the switch from controlled to compulsive behaviour. In particular, hypofunctioning of monoaminergic systems and hyperfunctioning of glutamatergic systems may play a role in compulsive alcohol drinking. [source] Methylone and mCPP, two new drugs of abuse?ADDICTION BIOLOGY, Issue 4 2005M. Bossong Recently, two new ecstasy-like substances, methylone and mCPP, were found in street drugs in the Netherlands by the Drugs Information and Monitoring System (DIMS). Methylone (3,4-methylenedioxymethcathinone) is the main ingredient of a new liquid designer drug that appeared on the Dutch drug market, called ,Explosion'. mCPP (meta-chlorophenylpiperazine) is a substance often used as a probe for the serotonin function in psychiatric research, and has now been found in street drugs, both in tablets and powders. Methylone as well as mCPP act on monoaminergic systems, resembling MDMA (3,4-methylenedioxymethamphetamine), with mCPP mainly affecting the serotonin system. The subjective effects of both new substances exhibit subtle differences with those of MDMA. Only little is known about the harmfulness of both methylone and mCPP. However, because of similarities between these substances and MDMA, risks common to MDMA cannot be excluded. [source] Effects of Long-Term Hormone Treatment and of Tibolone on Monoamines and Monoamine Metabolites in the Brains of Ovariectomised, Cynomologous MonkeysJOURNAL OF NEUROENDOCRINOLOGY, Issue 9 2006R. B. Gibbs The effects of long-term hormone treatment on monoamines and monoamine metabolites in different regions of the primate brain were examined and compared. Ovariectomised Cynomologous monkeys received daily oral administration of either conjugated equine oestrogens (CEE), CEE + medroxyprogesterone acetate (MPA), or a low or high dose of tibolone, for a period of 2 years. Tissue punches collected from frozen sections through various regions of the forebrain, midbrain, and hindbrain were assayed for levels of dopamine, dihydroxyphenylacetic acid (DOPAC), serotonin, 5-hydroxyindole acetic acid (5-HIAA), and norepinephrine by high-performance liquid chromatography. Few differences between hormone-treated animals and ovariectomised controls were observed. No statistically significant effects of CEE relative to controls were detected in any of the seven brain regions analysed. Animals treated with CEE + MPA showed significant reductions in 5-HIAA in the dorsal raphe nucleus, a significant reduction in dopamine in the hypothalamus, and a significant reduction in serotonin (5-HT) levels in area 8AD of the frontal cortex. Similar to CEE, no significant effects of tibolone relative to controls were detected; however, animals treated with high-dose tibolone showed a decrease in 5-HT levels in the frontal cortex that approached significance and was similar to the effect of CEE + MPA. Collectively, the findings suggest that long-term oral administration of these compounds has relatively few effects on the levels of dopamine, serotonin, and their primary metabolites in the primate brain. This differs from the significant effects on serotonergic and dopaminergic systems detected following parenteral treatment with oestradiol and progesterone, and likely reflects differences between the effects of treating with CEE + MPA versus oestradiol and progesterone on brain monoaminergic systems. [source] | ||||||||||