86,757 research outputs found
A surprising pattern of Sexual Dimorphism in the Eurasian otter (Lutra lutra) in Sweden
No full textSexual dimorphism is a very common strategy in polygamous mammals. In mustelids, sexual size dimorphism (SSD) is present in several species, while sexual shape dimorphism (SShD) is not as common. The Eurasian otter is a semiaquatic mustelid, exclusively feeding on aquatic prey, mainly fish, amphibians, and crustaceans. It is well-known that male otters tend to be larger, whereas information on SShD is contrasting. We used a 3D geometric morphometric approach to investigate SSD and SShD in three genetically distinct populations of otters located in Northern, Central and Southern Sweden. We analyzed 71 otter skulls (M=41, F=30), using photogrammetric techniques to produce 3D models of each skull, placing 30 3D landmarks on each model. We found that sexual dimorphism varies among populations. Neither SSD nor SShD occurred in the North, only SSD occurred in the Centre, and both SSD and SShD are present in the South of Sweden. Allometric trajectories of males and females from the North population differed from those of the other two populations. Our results highlighted a great variability in sexual dimorphism in Swedish Eurasian otters, that probably derives from different responses to prey availability and historical contingencies
Effective Analysis of Flexible Collaboration Processes by way of Abstraction and Mining Techniques
No full textEffects of Haloperidol on the expression of lymphocyte dopamine receptor mRNA in the rat
No full textIF 1.5
The recognition of facial emotion expressions in Parkinson's disease
No full textA limited number of studies in Parkinson's Disease (PD) suggest a disturbance of recognition of facial emotion expressions. In particular, disgust recognition impairment has been reported in unmedicated and medicated PD patients. However, the results are rather inconclusive in the definition of the degree and the selectivity of emotion recognition impairment, and an associated impairment of almost all basic facial emotions in PD is also described. Few studies have investigated the relationship with neuropsychiatric and neuropsychological symptoms with mainly negative results. This inconsistency may be due to many different problems, such as emotion assessment, perception deficit, cognitive impairment, behavioral symptoms, illness severity and antiparkinsonian therapy. Here we review the clinical characteristics and neural structures involved in the recognition of specific facial emotion expressions, and the plausible rote of dopamine transmission and dopamine replacement therapy in these processes. It is clear that future studies should be directed to clarify all these issues. (c) 2008 Elsevier B.V. and ECNP. All rights reserved
Rotigotine for anxiety during wearing-off in Parkinson's disease with dementia
No full textWearing-off (WO) refers to the exacerbation of motor and/or non-motor symptoms of Parkinson's disease at the end of dose of dopaminergic medications. Treatment of WO is based on modifying drug schedule, meal timetable and/or increasing dopamine replacement therapy. In advanced and/or demented patients, management of WO is often limited by scarce compliance and by cognitive, psychiatric and dysautonomic side-effects that may accompany increased dopaminergic stimulation
Functional correlates of nicotine administration: similarity with drugs of abuse.
No full texti.f. (2001) 3.49
Mapping of the pharmacological and toxicological effects of dopaminergic drugs in experimental animals
No full textFunctional consequences of pharmacological and toxicological manipulations of the dopaminergic systems were evaluated by means of the 2-[C-14]deoxyglucose (DG) method for measuring local rates of cerebral glucose utilization. Administration of dopamine agonist drugs modifies glucose metabolism in selected brain areas. Several factors, such as the compound used, the dose, length, and modality of the treatment, and the interval of time between the end of the treatment and the measurement of glucose utilization, contribute to define the topography and intensity of the changes. The differences refer to distinct activation of subtypes of dopamine receptors, to secondary involvement of other neurotransmitter receptor systems, and to modification of the receptor sensitivity occurring during the treatment. Other variables that interfere with the motivated behavior induced by psychostimulants may also affect the metabolic pattern. A few changes in glucose utilization are, however, common to most dopamine agonist drugs. High doses, which induce stereotypic behavior, produce metabolic changes in the extrapyramidal system. Low doses of psychostimulants, which elicit locomotion and exploratory behavior and produce reinforcement, increase glucose metabolism in the limbic system, particularly in the nucleus accumbens. Metabolic mapping in monkeys bearing 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced lesions of the dopaminergic areas in the brainstem contributed to define the key role of the striatopallidal pathway in the production and maintenance of the motor abnormalities that characterize parkinsonism. Metabolic patterns associated with unilateral 6-hydroxydopamine lesion of the nigrostriatal neurons in the rat are modified by dopamine agonist drugs. Specific changes are produced by selective D1 or D2 agonists. In rats bearing unilateral 6-hydroxydopamine lesion, the DG method also revealed functional effects produced by the interaction between D1 and N-methyl-D-aspartate receptors
Effects of nicotine on the nucleus accumbens and similarity to those of addictive drugs
No full textTHE question of whether nicotine, the neuroactive compound of tobacco, is addictive has been open to considerable scientific and public discussion. Although it can serve as a positive reinforcer in several animal species, including man, nicotine is thought to be a weak reinforcer in comparison with addictive drugs such as cocaine and heroin(1,2), and has been argued to be habit forming but not addictive(3,4). Here we report that intravenous nicotine in the rat, at doses known to maintain self-administration, stimulates local energy metabolism, as measured by 2-deoxyglucose autoradiography, and dopamine transmission, as estimated by brain microdialysis, in the shell of the nucleus accumbens. These neurochemical and metabolic effects are qualitatively similar to those of other drugs, such as cocaine, amphetamine and morphine, which have strong addictive properties(5-7). Our results provide functional and neurochemical evidence that there are specific neurobiological commonalities between nicotine and addictive drugs
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