title: In vivo imaging of dopaminergic neurotransmission after transient focal ischemia in rats.
abstract: The precise biologic mechanisms involved in functional recovery processes in response to stroke such as dopaminergic neurotransmission are still largely unknown. For this purpose, we performed in parallel in vivo magnetic resonance imaging and positron emission tomography (PET) with [(18)F]fluorodeoxyglucose ([(18)F]FDG) and [(11)C]raclopride at 1, 3, 7, 14, 21, and 28 days after middle cerebral artery occlusion in rats. In the ischemic territory, PET [(18)F]FDG showed a initial decrease in cerebral metabolism followed by a time-dependent recovery to quasi-normal values at day 14 after ischemia. The PET with [(11)C]raclopride, a ligand for dopamine D(2) receptor, showed a sustained binding during the first week after ischemia that declined dramatically from day 14 to day 28. Interestingly, a slight increase in [(11)C]raclopride binding was observed at days 1 to 3 followed by the uppermost binding at day 7 in the contralateral territory. Likewise, in vitro autoradiography using [(3)H]raclopride confirmed these in vivo results. Finally, the neurologic test showed major neurologic impairment at day 1 followed by a recovery of the cerebral function at day 28 after cerebral ischemia. Taken together, these results might suggest that dopamine D(2) receptor changes in the contralateral hemisphere could have a key role in functional recovery after cerebral ischemia.
authors.affiliation: Molecular Imaging Unit, CIC biomaGUNE, San Sebastián, Spain. amartin@cicbiomagune.es
authors.forename: Abraham
authors.initials: A
authors.lastname: Martín
authors.forename: Vanessa
authors.initials: V
authors.lastname: Gómez-Vallejo
authors.forename: Eneko
authors.initials: E
authors.lastname: San Sebastián
authors.forename: Daniel
authors.initials: D
authors.lastname: Padró
authors.forename: Irati
authors.initials: I
authors.lastname: Markuerkiaga
authors.forename: Irantzu
authors.initials: I
authors.lastname: Llarena
authors.forename: Jordi
authors.initials: J
authors.lastname: Llop
mesh_terms: D000818:Animals; D002545:Brain Ischemia / Q000000981:diagnostic imaging / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000494:pharmacology; D059290:Dopaminergic Neurons / Q000378:metabolism* / Q000473:pathology; D019788:Fluorodeoxyglucose F18 / Q000494:pharmacology; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000378:metabolism; D008297:Male; D049268:Positron-Emission Tomography; D020891:Raclopride / Q000494:pharmacology; D011859:Radiography; D019275:Radiopharmaceuticals / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017448:Receptors, Dopamine D2; D020521:Stroke / Q000000981:diagnostic imaging / Q000378:metabolism*; D009435:Synaptic Transmission; D013997:Time Factors
chemical_list: D018492:Dopamine Antagonists; D019275:Radiopharmaceuticals; D017448:Receptors, Dopamine D2; D019788:Fluorodeoxyglucose F18; D020891:Raclopride