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In the dorsal striatum, there are two major populations of medium spiny projection neurons. One population is positive for dynorphin mRNA (DYN+), and these cells project preferentially to the substantia nigra, forming the so-called 'direct pathway'. A second population is positive for enkephalin mRNA (ENK+), and these cells influence the substantia nigra(More)
RATIONALE It is known that social defeat can modulate cocaine self-administration. However, it is unclear whether this psychosocial stressor affects drug-taking behavior to the same extent across all individual animals, particularly those with differing propensities to self-administer psychostimulants. OBJECTIVE This study examined the effect of social(More)
The context in which amphetamine is administered modulates its ability to induce both behavioral sensitization and immediate early gene expression. When given in a novel test environment amphetamine produces greater levels of c-fos and arc mRNA expression in many brain regions relative to when it is given in the home cage. The purpose of the current study(More)
BACKGROUND Alterations of serotonin neurotransmission are implicated in both mood disorders and schizophrenia. Specific serotonin-receptor-based abnormalities in these psychiatric illnesses have been intensively studied; however, it has been difficult to draw any conclusions because of a lack of consensus. These inconsistencies have most likely arisen from(More)
When administered in a novel environment relatively low doses of amphetamine induce c-fos mRNA in the subthalamic nucleus (STN) and in preproenkephalin mRNA-containing (ENK+) neurons in the caudate-putamen (CPu). When administered at home, however, low doses of amphetamine do not produce these effects. Environmental novelty also facilitates the behavioral(More)
Dopamine (DA) and glutamate neurotransmission is thought to be critical for psychostimulant drugs to induce immediate early genes (IEGs) in the caudate-putamen (CPu). We report here, however, that the ability of DA and glutamate NMDA receptor antagonists to attenuate amphetamine-evoked c-fos mRNA expression in the CPu depends on environmental context. When(More)
The ability of amphetamine or cocaine to induce the expression of c-fos mRNA in a number of brain regions is greatly enhanced when these drugs are administered in a distinct and relatively novel environment, relative to when they are given in the home cage. The purpose of this study was to determine if environmental context has a similar effect on the(More)
Although nociceptin/orphanin FQ (N/OFQ) influences dopamine (DA) neuronal activity, it is not known whether N/OFQ acts directly on DA neurons, indirectly by means of local circuitry, or both. We used two parallel approaches, dual in situ hybridization (ISH) and neurotoxic lesions of DA neurons by using 6-hydroxydopamine (6-OHDA), to ascertain whether N/OFQ(More)
BACKGROUND Anterior structural damage to the anal sphincter occurs in up to a third of women at first vaginal delivery, and of these a third have new bowel symptoms. The standard treatment for such structural damage is anterior overlapping anal-sphincter repair. We aimed to assess the long-term results of this operation. METHODS We assessed the long-term(More)
OBJECTIVE Clinical parameters such as grade, size and/or location of the tumor are good predictors of outcome in patients with astrocytoma. The objective of this study was to determine whether DNA content parameters have a prognostic significance for this group of tumors. METHODS Following optimization and validation of methodology for evaluating cellular(More)