Effects of intraventricular 6-hydroxydopamine on cerebrovascular CO2 reactivity in anesthetized rats.

Regional cerebral blood flow was measured by the 14C-ethanol technique in anesthetized rats before and after intraventricular injection of 6-hydroxydopamine. This treatment reduced the fluorescence of the central noradrenaline and dopamine nerve terminals, as well as of the perivascular nerve terminals in cerebral vessels. The administration of 6-hydroxydopamine had no significant effect on cerebral blood flow at normocapnia. The cerebrovascular reactivity to hypercapnia was significantly increased in the 6-hydroxydopamine treated animals. The results indicate an involvement of central catecholamine pathways in the cerebrovascular reactivity to hypercapnia.