| Popis |
Background: Neurovascular coupling links neural activity to regional cerebral blood flow (rCBF), a process modulated by neurotransmitters such as serotonin, histamine, and dopamine. Arterial spin labeling (ASL) MRI enables non-invasive assessment of rCBF changes, offering insights into pharmacologically induced neurovascular dynamics. While serotonergic and histaminergic agents are known to influence vascular tone, the acute cerebral perfusion effects of these compounds, as well as the stimulant methamphetamine (METH), remain incompletely understood. Methods: Using ASL-MRI at 9.4 T (Bruker BioSpec 94/30 USR), we investigated acute rCBF changes in male Sprague-Dawley rats following administration of serotonergic (sumatriptan, escitalopram, palonosetron), histaminergic (2-pyridylethylamine, mepyramine), and indirect catecholaminergic (methamphetamine) drugs. Region-specific rCBF was measured in the sensorimotor cortex, piriform cortex, hippocampus, thalamus, Circle of Willis, and whole brain. Results: Sumatriptan significantly increased rCBF in the sensorimotor cortex and thalamus, while escitalopram and palonosetron had no effect. The H1 agonist 2-pyridylethylamine increased rCBF in the whole brain, sensorimotor cortex, and thalamus, whereas the inverse H1 agonist mepyramine showed no effect. Methamphetamine induced a robust, dose-dependent increase in rCBF across all regions except the Circle of Willis, with the peak effect in the thalamus at 40 minutes post-injection. Baseline perfusion varied by region, with the Circle of Willis showing the highest flow and cortical areas the lowest. Conclusion: These findings demonstrate that serotonergic, histaminergic, and dopaminergic systems acutely and differentially modulate rCBF in a region-specific and dose-dependent manner. ASL-MRI is a sensitive tool for detecting these perfusion changes and may support preclinical screening of neuroactive compounds targeting vascular or neurotransmitter pathways.
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