Regional changes in human cerebral blood flow during dipyridamole stress: neural activation in the thalamus and prefrontal cortex.
Intravenous dipyridamole increases the concentration of circulating adenosine and produces coronary vasodilation. However, it decreases global cerebral blood flow (CBF) due to hyperventilation side effect of adenosine. In the present study, changes in regional CBF during dipyridamole stress were identified in detail. In 11 healthy men (51-71 years of age), CBF was measured by positron emission tomography with oxygen-15-labeled water at rest (baseline) and during dipyridamole stress. All images were normalized to global CBF and transformed to standard brain anatomy. A t map between baseline and dipyridamole stress conditions was then created on a pixel-by-pixel basis. CBF was globally decreased during dipyridamole stress. However, a significant relative increase in CBF was observed bilaterally in the thalamus and prefrontal cortex, indicating neural activation in these regions. Adenosine plays an important role in the production of anginal pain by stimulation of A(1) adenosine receptors. Neural activation in the thalamus and prefrontal cortex during angina pectoris has been reported. Although no subject felt chest pain during dipyridamole stress, neural activation in the thalamus and prefrontal cortex indicates that stimulation of A(1) adenosine receptors during dipyridamole stress may produce input from the heart to the thalamus through the vagal fiber.
Ito
Hiroshi
H
Department of Radiology and Nuclear Medicine, Akita Research Institute of Brain and Blood Vessels, Akita, Japan.
Yokoyama
Ikuo
I
Tamura
Yoshikazu
Y
Kinoshita
Toshibumi
T
Hatazawa
Jun
J
Kawashima
Ryuta
R
Iida
Hidehiro
H
D001794:Blood Pressure / Q000187:drug effects; D001931:Brain Mapping / Q000379:methods; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D004176:Dipyridamole / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D010104:Oxygen Radioisotopes; D017397:Prefrontal Cortex / Q000098:blood supply* / Q000000981:diagnostic imaging; D013312:Stress, Physiological; D013788:Thalamus / Q000098:blood supply* / Q000000981:diagnostic imaging; D014055:Tomography, Emission-Computed / Q000379:methods; D014665:Vasodilator Agents / Q000494:pharmacology*
D010104:Oxygen Radioisotopes; D014665:Vasodilator Agents; D004176:Dipyridamole