Arterial spin labeling demonstrates that focal amygdalar glutamatergic agonist infusion leads to rapid diffuse cerebral activation

Abstract

Objectives-To investigate acute effects of intra-amygdalar excitatory amino acid administration on blood flow, relaxation time and apparent diffusion coefficient in rat brain.Materials and Methods-Several days after MR-compatible cannula placement in right basolateral amygdala, anesthetized rats were imaged at 7T. Relative CBF was measured before and 60 minutes after infusion of 10 nanomoles KA, cAMPA, ATPA, or normal saline using arterial spin labeling. Quantitative T 2 and diffusion weighted images were acquired. rCBF, T 2 and ADC values were evaluated in bilateral basolateral amygdala, hippocampus, basal ganglia, frontal and parietal regions.Results-KA led to the highest, and ATPA lowest bilateral rCBF increases. Time courses varied among drugs. T 2 for KA and AMPA was higher while ADC was lower for KA.Conclusions-Intraamygdalar injection of GluR agonists evoked bilateral seizure activity and increased rCBF, greater for KA and AMPA than selective ATPA GluR5 activation.

Early stratification of radiotherapy response by activatable inflammation magnetic resonance imaging

“…Reconstruction of the aiMRI maps. All the simulations were performed on homewritten programs 49 in MATLAB 2018a (MathWorks, Natick, MA, USA). In the phantom experiments where the signal in some voxels reached noise floor at large TEs, the signal correction for Rician noise was performed.…”

Isolated seizures in rats do not cause neuronal injury

“…In a previous study, we found that intra-amygdalar injection of 10 nm KA, AMPA or ATPA GluR agonists evoked bilateral seizure activity and increased rCBF (6). In this study, we sought to determine whether isolated seizures, whether single or repetitive, induced by threshold doses of excitatory amino acids (EAAs), and not leading to status epilepticus, would lead to structural and pathological changes in rats.…”