Neural transplants disrupt the blood-brain barrier and allow peripherally acting drugs to exert a centrally mediated behavioral effect.

The disruption of the blood-brain barrier (BBB) following neural transplantation has been demonstrated with horseradish peroxidase histochemistry. It appears that the BBB becomes at least temporarily permeable to large macromolecules. In this study, two drugs (N-methylscopolamine and domperidone) that do not normally cross the BBB were shown to exert a centrally mediated behavioral effect when systematically administered in transplanted rats. This demonstrates that N-methylscopolamine, domperidone, and perhaps other peripherally acting drugs can enter the brain via transplants and directly modify CNS function.