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Dopaminergic Drugs (dopaminergic + drug)

Distribution by Scientific Domains
Medical Sciences77%

Selected Abstracts

Dopamine gene predicts the brain's response to dopaminergic drug

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2007
Michael X Cohen
Abstract Dopamine is critical for reward-based decision making, yet dopaminergic drugs can have opposite effects in different individuals. This apparent discrepancy can be accounted for by hypothesizing an ,inverted-U' relationship, whereby the effect of dopamine agents depends on baseline dopamine system functioning. Here, we used functional MRI to test the hypothesis that genetic variation in the expression of dopamine D2 receptors in the human brain predicts opposing dopaminergic drug effects during reversal learning. We scanned 22 subjects while they engaged in a feedback-based reversal learning task. Ten subjects had an allele on the Taq1A DRD2 gene, which is associated with reduced dopamine receptor concentration and decreased neural responses to rewards (A1+ subjects). Subjects were scanned twice, once on placebo and once on cabergoline, a D2 receptor agonist. Consistent with an inverted-U relationship between the DRD2 polymorphism and drug effects, cabergoline increased neural reward responses in the medial orbitofrontal cortex, cingulate cortex and striatum for A1+ subjects but decreased reward responses in these regions for A1, subjects. In contrast, cabergoline decreased task performance and fronto-striatal connectivity in A1+ subjects but had the opposite effect in A1, subjects. Further, the drug effect on functional connectivity predicted the drug effect on feedback-guided learning. Thus, individual variability in how dopaminergic drugs affect the brain reflects genetic disposition. These findings may help to explain the link between genetic disposition and risk for addictive disorders. [source]

Dopamine challenge tests as an indicator of psychological traits

HUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 2 2006
P. Netter
Abstract After discussing some introductory considerations about the value of challenge tests in general for discriminating personality dimensions which are considered extrapolations of psychopathological diseases, the present paper outlines the matter of responsivity to agonistic and antagonistic dopaminergic drugs or drugs of different mechanisms of action in the dopaminergic system, and elucidates that different hormones elicited by dopaminergic substances (prolactin, growth hormone) may indicate personality related differences in susceptibility of different brain areas. A further point was to demonstrate not only the well known relationship of dopaminergic hyperactivity with reward seeking and motivational factors associated with extraversion and novelty seeking, but also the relationship of dopaminergic hypofunction with the personality dimension of depression which had already been reported in studies on animals and psychiatric patients. A final point was to demonstrate that besides size of hormone responses additional parameters like time of response onset and initial prolactin increase can be used as biochemical indicators for identifying certain personality types, like highly depressive neurotic persons characterized by lower and later dopamine responses as compared to low depressives, and extraverted sensation-seeking types responding by an initial prolactin peak as opposed to low sensation seekers. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Basal ganglia physiology and deep brain stimulation,

MOVEMENT DISORDERS, Issue S1 2010
Andres M. Lozano FRCSC
Abstract Despite improvements in anatomic imaging of the basal ganglia, microelectrode recording is still an invaluable tool in locating appropriate targets for neurosurgical intervention. These recording also provide an unparalleled opportunity to study the pathophysiological aspects of diseases. This article reviews the principles of microelectrode recording in functional neurosurgery and discusses the pathologic neurophysiologic findings commonly encountered. It also highlights some of the potential mechanisms of action of both dopaminergic drugs and deep brain stimulation. In addition we review the recent work on pedunculopontine nucleus neurophysiology and trials of deep brain stimulation in that region for gait disturbances in Parkinson's disease. © 2010 Movement Disorder Society [source]

Amantadine may reverse punding in Parkinson's disease,Observation in a patient

MOVEMENT DISORDERS, Issue 1 2008
Kenichi Kashihara MD
Abstract Punding, complex stereotyped behavior, sometimes occurs in patients with Parkinson's disease under dopaminergic replacement therapy. Reduction of dopaminergic drugs may reduce the problem but risks enhancing motor impairment. We report a patient with Parkinson's disease presenting disabling punding, which was reversed by amantadine without aggravating motor function. Amantadine may reduce punding by blocking NMDA receptors, in the same manner as in levodopa-induced dyskinesias. © 2007 Movement Disorder Society [source]

Dopamine transporter: Basic aspects and neuroimaging

MOVEMENT DISORDERS, Issue S7 2003
Paola P. Piccini MD
Abstract The plasma membrane dopamine transporter (DAT) is found exclusively in dopamine neurones and seems to be the defining molecule of the dopamine neurone. It provides effective control over the intensity of dopamine-mediated signalling by recapturing the neurotransmitter released by presynaptic neurones. Positron emission tomography (PET) and single-photon emission computed tomography (SPECT) represent unique techniques for assessing in vivo DAT distribution in humans and offer reliable methods for studying nigrostriatal dopaminergic function in health and disease. The characteristics of different DAT radiotracers, the modifying influences of factors such as age, gender, smoking habit, and dopaminergic drugs on DAT transporters as well as their implication in evaluation of neuroimaging studies are discussed. © 2003 Movement Disorder Society [source]

Drug-induced confusional states: the usual suspects?

ACTA NEUROLOGICA SCANDINAVICA, Issue 6 2009
A. Hufschmidt
Background,,, Acute confusional state (ACS) is a frequent reason for hospital admission. This study examines retrospectively the frequency by which individual drugs were found responsible for ACS. Results,,, Drug-induced ACS was found in 65 (18.8%) of 346 hospital admissions for acute confusion. The most frequent causative substances were dopaminergic drugs in Parkinsonian patients (24.2%), diuretics (15.1%), tricyclic or tetracyclic antidepressants (13.6%) and benzodiazepines (13.6%). Almost half of the patients were demented, and in one-third of these, dementia had not been diagnosed hitherto. Conclusion,,, The data suggest that diuretics by way of causing hyponatraemia are as relevant a cause of ACS as dopaminergic or anticholinergic substances. [source]

Features associated with the development of hallucinations in Parkinson's disease

ACTA NEUROLOGICA SCANDINAVICA, Issue 4 2006
G. Benbir
Objective ,, To identify features related to the development of hallucinations in Parkinson's disease (PD). Materials and methods ,, Seventy PD patients with hallucinations (group 1) and 60 PD patients without hallucinations (group 2) were evaluated for disease severity, presence of motor complications, rapid eye movement (REM) behavior disorder (RBD), and antiparkinsonian drug profile. The ages at the emergence of hallucinations and duration of disease in group 1 were matched with the ages at the last visit of those in group 2. Results ,, Disease severity and presence of motor complications were similar in both groups. RBD was more frequently encountered among hallucinators than among non-hallucinators (P = 0.007). The mean duration and daily doses of levodopa and other dopaminergic drugs did not differ in both groups; however, the usage of anticholinergics and amantadine were significantly more frequent in group 2, unexpectedly. Conclusions ,, The presence of RBD was significantly more common in hallucinators; however, severity of PD, duration and daily doses of dopaminergic drugs were not associated with the emergence of hallucinations. [source]