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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2004-8-24
pubmed:abstractText
The mechanisms underlying the signal changes observed with pharmacological magnetic resonance imaging (phMRI) remain to be fully elucidated. In this study, we obtained microdialysis samples in situ at 5-min intervals during phMRI experiments using a blood pool contrast agent to correlate relative cerebral blood volume (rCBV) changes with changes in dopamine and cocaine concentrations following acute cocaine challenge (0.5 mg/kg iv) in the rat over a duration of 30 min. Three brain areas were investigated: the dorsal striatum (n = 8), the medial prefrontal cortex (mPFC; n = 5), and the primary motor cortex (n = 8). In the striatum and mPFC groups, cocaine and dopamine temporal profiles were tightly correlated, peaking during the first 5-min period postinjection, then rapidly decreasing. However, the local rCBV changes were uncorrelated and exhibited broader temporal profiles than those of cocaine and dopamine, attaining maximal response 5-10 min later. This demonstrates that direct vasoactivity of dopamine is not the dominant component of the hemodynamic response in these regions. In the motor cortex group, microdialysis revealed no local change in dopamine in any of the animals, despite large local cocaine increase and strong rCBV response, indicating that the central hemodynamic response following acute iv cocaine challenge is not driven directly by local dopamine changes in the motor cortex. The combination of phMRI and in situ microdialysis promises to be of great value in elucidating the relationship between the phMRI response to psychoactive drugs and underlying neurochemical changes.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
1053-8119
pubmed:author
pubmed:issnType
Print
pubmed:volume
23
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
296-304
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:15325377-Animals, pubmed-meshheading:15325377-Blood Volume, pubmed-meshheading:15325377-Brain, pubmed-meshheading:15325377-Cocaine, pubmed-meshheading:15325377-Corpus Striatum, pubmed-meshheading:15325377-Dopamine, pubmed-meshheading:15325377-Dose-Response Relationship, Drug, pubmed-meshheading:15325377-Half-Life, pubmed-meshheading:15325377-Hemodynamics, pubmed-meshheading:15325377-Image Processing, Computer-Assisted, pubmed-meshheading:15325377-Infusions, Intravenous, pubmed-meshheading:15325377-Magnetic Resonance Imaging, pubmed-meshheading:15325377-Mass Spectrometry, pubmed-meshheading:15325377-Microdialysis, pubmed-meshheading:15325377-Motor Cortex, pubmed-meshheading:15325377-Prefrontal Cortex, pubmed-meshheading:15325377-Rats, pubmed-meshheading:15325377-Reference Values, pubmed-meshheading:15325377-Regional Blood Flow
pubmed:year
2004
pubmed:articleTitle
Concurrent pharmacological MRI and in situ microdialysis of cocaine reveal a complex relationship between the central hemodynamic response and local dopamine concentration.
pubmed:affiliation
Department of Neuroimaging, Psychiatry Centre of Excellence in Drug Discovery, GlaxoSmithKline Medicines Research Centre, 37135 Verona, Italy.
pubmed:publicationType
Journal Article