ABSTRACT
Acknowledgments ............................................................................................ 305
References ........................................................................................................ 305
A large number of hydrophilic molecules, such as peptides, proteins, and
oligonucleotides, are poorly taken up by cells since they do not efficiently cross
the lipid bilayer of the plasma membrane. This is considered to be a major limitation
for their use as therapeutic agents in biomedical research and in the pharmaceutical
industry. In particular, it has been widely accepted that peptide neuromodulators
fail to significantly affect their target cells within the brain when administered
peripherally. This is likely to be due to the existence of the blood-brain barrier
(BBB), a complex biological interface, which prevents transport of most drugs from
the vasculature into the brain parenchyma.