[Changes in the local cerebral blood flow during the microdialysis administration of vasoactive substances].

The authors suggest the construction of a cannula for microdialysis combined with a light guide of a laser doppler flowmeter. Such a design allows monitoring of blood flow intensity in the environment of the microdialyzer. An advantage of local administration of vasoactive agents is that they cause no effect on systemic arterial pressure. When administered locally, sodium nitroprusside increased whereas the inhibitor NO-synthase reduced blood flow intensity. No changes were detected in the local blood flow in administration of phenylephrine and nitroglycerin through the dialyzer. Tetrodoxin insignificantly reduced the blood flow. The existence of a diffusion barrier for some agents as well as the long period of time needed for attaining the state of equilibrium after beginning perfusion of the solution containing the agent under test is among the disadvantages of local administration.