The effects of hyper- and hypocarbia on intraparenchymal arterioles in rat brain slices.
This investigation examined the direct effects of hyper- and hypocarbia on intracerebral resistance vessels within an intact neuronal synctium. Hippocampal rat brain slices were superfused with artificial cerebrospinal fluid (aCSF). Arterioles were located and diameter changes in response to alterations in aCSF carbon dioxide tension (pCO2) were monitored with videomicroscopy. Microvessels dose dependently dilated and constricted during hyper- and hypocarbia, respectively. A two-fold rise in pCO2 produced a 20% increase in diameter, while a 47% decrease in pCO2 vasoconstricted microvessels by 11%. This is the first model allowing the investigation of the direct actions of physiologic mediators on discrete intracerebral resistance vessels in situ. The results suggest that intracerebral microvessels significantly respond to changes in pCO2 and may be intimately involved in alterations in cerebral vascular resistance.
Harkin
C P
CP
Department of Anesthesiology, Medical College of Wisconsin, Children's Hospital of Wisconsin, Milwaukee 53226, USA.
Schmeling
W T
WT
Kampine
J P
JP
Farber
N E
NE
D000818:Animals; D001160:Arterioles / Q000473:pathology; D002245:Carbon Dioxide / Q000378:metabolism; D002560:Cerebrovascular Circulation / Q000502:physiology; D006624:Hippocampus / Q000098:blood supply / Q000473:pathology*; D006863:Hydrogen-Ion Concentration; D006935:Hypercapnia / Q000473:pathology*; D016857:Hypocapnia / Q000473:pathology*; D066298:In Vitro Techniques; D008297:Male; D010477:Perfusion; D051381:Rats; D017207:Rats, Sprague-Dawley; D014664:Vasodilation / Q000502:physiology
D002245:Carbon Dioxide