Arterial spin labeling demonstrates that focal amygdalar glutamatergic agonist infusion leads to rapid diffuse cerebral activation.
OBJECTIVE
To investigate acute effects of intra-amygdalar excitatory amino acid administration on blood flow, relaxation time and apparent diffusion coefficient in rat brain.


METHODS
Several days after MR-compatible cannula placement in right basolateral amygdala, anesthetized rats were imaged at 7 T. Relative cerebral blood flow (CBF) was measured before and 60 min after infusion of 10 nmol 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
Intra-amygdalar injection of GluR agonists evoked bilateral seizure activity and increased rCBF, greater for KA and AMPA than selective ATPA GluR5 activation.
Munasinghe
J P
JP
MRI Research Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA.
Banerjee
M
M
Acosta
M T
MT
Banks
M
M
Heffer
A
A
Silva
A C
AC
Koretsky
A
A
Theodore
W H
WH
D000679:Amygdala / Q000098:blood supply* / Q000187:drug effects*; D000818:Animals; D001158:Arteries / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D001931:Brain Mapping; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods; D004195:Disease Models, Animal; D004569:Electroencephalography; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology*; D007839:Functional Laterality / Q000187:drug effects / Q000502:physiology; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008297:Male; D051381:Rats
D018690:Excitatory Amino Acid Agonists