[Effect of carbidopa and dimethyl sulfoxide on the permeability of the hemato-encephalic barrier for 14C-tyrosine and 14C-DOPA in rats].

Carbidopa at a dose 40 and 80 mg/kg, i.p. had no effect on BBB permeability for 14C-tyrosine but increased in a dose-dependent manner the penetration of 14C-DOPA into the brain. DMSO at a dose 1.75, 3.5 and 7 g/kg, i.p. increased the BBB permeability for both isotopes but to a greater extent for the labeled tyrosine. Carbidopa combined with DMSO produced more marked increase of BBB permeability for 14C-DOPA in comparison to their separate application and had no effect on 14C-tyrosine penetration. It is suggested that the increased passage of DOPA through the BBB can be achieved by weakening of the enzymatic component of the BBB as well as by the activation of unspecific transport mechanisms (pinocytosis) of the BBB.