Effect of decreased glucose concentration on cerebrovascular tone in vitro.
We studied the effect of decreased glucose concentration on cerebrovascular tone in vitro. Segments of rat middle cerebral arteries (MCA) were isolated, cannulated at both ends with glass micropipettes, and pressurized to 85 mm Hg. Decreasing the glucose in the extraluminal bath and luminal perfusate from 5.5 mmol/L to 1.0 or 0.5 mmol/L for 1.5 hours each had no significant effect on the diameter of the arteries. When all the glucose was removed from the extraluminal bath and luminal perfusate for 1.5 hours, the MCA dilated by 23% [252 +/- 24 (SD) microns to 311 +/- 7 microns (P < .5, n = 7)]. This dilation was 80% of the maximum dilation produced by removal of Ca+2 from the bathing solutions. Neither removal of the endothelium nor inhibition of the ATP-sensitive K channels with 10(-5) mol/L glibenclamide altered the response of the isolated MCA to the removal of glucose. We conclude that rat MCA are relatively more resistant to substrate limitation compared to the brain as a whole.
Swafford
M W
MW
Department of Anesthesiology, Baylor College of Medicine, Houston, Texas.
Raty
S
S
Childres
W F
WF
Bryan
R M
RM
D018528:ATP-Binding Cassette Transporters; D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D002536:Cerebral Arteries / Q000187:drug effects* / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D005905:Glyburide / Q000494:pharmacology*; D007003:Hypoglycemia / Q000503:physiopathology*; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D054086:KATP Channels; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology; D024661:Potassium Channels, Inwardly Rectifying; D051381:Rats; D012701:Serotonin / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects* / Q000502:physiology
D018528:ATP-Binding Cassette Transporters; D001786:Blood Glucose; D007004:Hypoglycemic Agents; D054086:KATP Channels; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; C092520:uK-ATP-1 potassium channel; D012701:Serotonin; D005905:Glyburide