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On the basis of the D(1/5)-selective dopamine antagonist LE 300 (1), an indolo[3,2-f]benzazecine derivative, we changed the annulation pattern of the heterocycles. The target compounds represent novel heterocyclic ring systems. The most constrained indolo[4,3a,3-ef]benzazecine 2 was inactive, but the indolo[4,3a,3-fg]benzazacycloundecene 3 showed antagonistic properties (functional Ca(2+) assay) with nanomolar affinities (radioligand binding) for all dopamine receptor subtypes, whereas the indolo[2,3-f]benzazecine 4 displayed a selectivity profile similar to 3 but with decreased affinities.
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http://dx.doi.org/10.1021/jm901291r | DOI Listing |
Psychogeriatrics
September 2025
Clinical Neurosciences and Mental Health Department, Faculty of Medicine of Porto University, Porto, Portugal.
The dopaminergic system may be at the base of some neurobehavioral symptoms, as apathy and depression, and extrapyramidal symptoms, often seen in Alzheimer's disease patients. It can also have an impact on cognitive decline, as extrapyramidal symptoms, classically linked with dopamine dysfunction, are associated with increased risk of cognitive impairment and Alzheimer's disease progression. We review the knowledge of the dopaminergic system, emphasizing changes in Alzheimer's disease.
View Article and Find Full Text PDFNeuropsychiatr Dis Treat
August 2025
Department of Psychiatry and Behavioral Sciences, New York Medical College, Valhalla, New York, USA.
Brexpiprazole is a second-generation antipsychotic with multiple indications, including the treatment of schizophrenia. As a partial dopamine agonist, brexpiprazole differs from most other antipsychotics, yet uncertainties about its full mechanism of action have led to some ambiguity among prescribers. To address this gap, an international panel of psychiatric experts was organized and convened with funding from Otsuka Pharmaceutical Europe Ltd and H.
View Article and Find Full Text PDFFront Biosci (Landmark Ed)
August 2025
Department of Biomedical Sciences, University of Missouri-Kansas City, School of Medicine, Kansas City, MO 64108, USA.
Glutamate is an important neurotransmitter in the mammalian brain. Among the receptors that glutamate interacts with is metabotropic glutamate (mGlu) receptor 2, a Gα-coupled receptor. These receptors are primarily located on glutamatergic nerve terminals and act as presynaptic autoreceptors to produce feedback inhibition of glutamate release.
View Article and Find Full Text PDFJ Cereb Blood Flow Metab
September 2025
Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA.
Preclinical PET studies offer the opportunity to elucidate molecular mechanisms underlying early neurodevelopment with minimal invasiveness. We demonstrated the feasibility of fetal brain PET in four pregnant rats ( = 42 fetuses). [F]FDG uptake in rat fetuses was readily visualized by PET imaging.
View Article and Find Full Text PDFPsychol Med
September 2025
https://ror.org/03cv38k47University of Groningen, University Medical Centre Groningen, Center for Clinical Neuroscience and Cognition, Groningen, The Netherlands.
Background: After remission of a first-episode psychosis (FEP), antipsychotic discontinuation is associated with an increased risk of relapse compared to maintenance treatment. We studied short and longer-term effects of discontinuation of D receptor (DR) antagonist and partial agonist antipsychotics on striatal dopamine DR availability in FEP patients.
Methods: Remitted FEP patients underwent two [C]raclopride PET scans to measure striatal DR availability: 1 week after antipsychotic discontinuation (n = 16 antagonist users, n = 6 partial agonist users) and after being medication free for 6-8 weeks (n = 8 antagonist users, n = 5 partial agonist users).