Regulation of intracranial pressure in the rat with chronic moderate hypercapnia.
OBJECTIVE
In this animal study we investigated whether CO2-induced intracranial hypertension was sustained in chronic hypercapnia.


METHODS
We kept five rats in a 10% CO2-air mixture (PaCO2 73.4 +/- 6.2 Torr, mean +/- 1SD) for 22 weeks, and then measured the rats' intracranial pressure while breathing the 10% CO2- air mixture or the room air.


RESULTS
The intracranial pressures recorded during chronic hypercapnia in systole and diastole were 7.0 +/- 1.9 and 5.4 +/- 1.6 mm Hg, respectively. When the rats were acutely exposed to the room air (PaCO2, 51.9 +/- 10.2 Torr), the intracranial pressures in systole and diastole were 6.1 +/- 1.4 and 5.0 +/- 0.8 mm Hg, respectively, were not significantly different from those during hypercapnia (P>0.05, paired t-test).


CONCLUSIONS
The intracranial pressure in rats with chronic moderate hypercapnia was not significantly different from normocapnic rats, and this change was associated with a blunting of intracranial pressure autoregulation.
Kumagai
M
M
Department of Internal Medicine, Tokai University School of Medicine, Isehara, Kanagawa, Japan.
Kondo
T
T
Takei
F
F
Kanayama
I
I
Ohta
Y
Y
D000818:Animals; D001784:Blood Gas Analysis; D001794:Blood Pressure; D002245:Carbon Dioxide; D002908:Chronic Disease; D006935:Hypercapnia / Q000503:physiopathology*; D007427:Intracranial Pressure / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar
D002245:Carbon Dioxide