Blood-brain barrier transport mechanism

Blood-brain barrier transport mechanism is not a single molecule or receptor, but a collective term for various highly specialized molecular systems that control the movement of substances between the bloodstream and the brain. It comprises a network of endothelial cells, transport proteins, and associated cellular structures in the blood-brain barrier (BBB) that regulate nutrient delivery, waste clearance, and drug permeability[1][2][3][4][5]. Blood-brain barrier transport mechanisms consist of various highly selective molecular systems that mediate the exchange of nutrients, ions, metabolic products, and drugs between the bloodstream and the central nervous system. These mechanisms include passive and facilitated diffusion, active transport via specialized transporter proteins, receptor-mediated transcytosis for larger molecules, and efflux pumps that restrict drug and toxin accumulation in the brain. The BBB selectively protects the brain, creates therapeutic challenges by restricting drug entry, and when dysfunctional, is implicated in diverse neurological diseases[1][2][3][4][5].

Other names

Blood-brain barrier transport mechanismsbrain endothelial transport systems

Passive diffusion (small lipophilic molecules) Facilitated diffusion (via specific solute carrier proteins, e.g., for glucose, amino acids) Active transport (ATPases, ABC transporters) Receptor-mediated transcytosis (e.g., transferrin or insulin) Efflux transport (P-glycoprotein, MRP family)