The response of the choroidal and cerebral circulations to changing arterial PCO2 and acetazolamide in the baboon.

Having established control values for choroidal and cerebral blood flow in twelve baboons, the response of both circulations to changing arterial PCO2 and intravenous acetazolamide was studied. The blood flow in both circulations varied directly with the PACO2, the magnitude of the response being very similar. There was a 3.6 percent change in both choroidal and cerebral blood flow per millimeter of mercury change in PACO2. Intravenous acetazolamide (25 mg./kg.) produced an increase in flow lasting approximately 50 minutes in both cerebral and choroidal circulations.