Increase in extracellular dopamine in the striatum during cerebral ischemia: a study utilizing cerebral microdialysis.
Unilateral ligation of the left common carotid artery in anesthetized Mongolian gerbils resulted in a steep rise in extracellular dopamine in the ipsilateral striatum in 9 out of 19 animals. Extracellular dopamine was measured by cerebral dialysis in vivo and reached a peak of 0.19 mM at 40 min. At the same time, the level of homovanillic acid fell, whereas the levels of ascorbate and 3,4-dihydroxyphenylacetic acid remained relatively constant. In a separate group of animals studied with a combined dialysis/electrochemistry probe, a rise in the in vivo chronoamperometric signal in three out of six animals correlated with a rise in extracellular dopamine. The number of animals responding in these experiments (roughly 50%) corresponds to the frequency of incompetent Circle of Willis, as well as literature reports of the frequency of signs of stroke in unanesthetized gerbils. These results show a remarkable accumulation of dopamine in extracellular fluid in response to cerebral ischemia. Released dopamine appears to be responsible for the elevated in vivo electrochemical signal previously reported.
Slivka
A
A
Graduate School of Biomedical Science (Neurobiology), Mount Sinai School of Medicine, City University of New York, NY 10029.
Brannan
T S
TS
Weinberger
J
J
Knott
P J
PJ
Cohen
G
G
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D002545:Brain Ischemia / Q000378:metabolism*; D002339:Carotid Arteries; D003342:Corpus Striatum / Q000378:metabolism*; D003956:Dialysis; D004298:Dopamine / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism*; D005849:Gerbillinae; D006719:Homovanillic Acid / Q000378:metabolism; D007700:Kinetics; D008026:Ligation; D008297:Male
D015102:3,4-Dihydroxyphenylacetic Acid; D004298:Dopamine; D006719:Homovanillic Acid