PHRM30002 Lecture Notes - Lecture 13: Astrocyte, Barrier Function, Kernicterus
13 Sep 2018
School
Department
Course
Professor
Document Summary
Bulk flow removes compounds from csf & brain. Export lipid soluble and modified compounds: functional barriers present at all stages of development, no mw cut-off. Combine structural (passive) and functional (active) components. Restricts entry of things not required (including many drugs) Extensive blood supply: 20% of cardiac output. Cerebral capillaries endothelium: site of the bbb, pericytes and astrocytes sits around, squamous cells. Cytoplasm much wider long diffusion path. Absence of fenestration (=window) and few pinocytotic vesicles no aqueous pathway. Blood can pass out to choroid plexus cells to generate csf. Fetal csf contains more protein than adult only adult ependyma bcb allows free exchange. Measures how a compound distributes b/n aqueous and non-aqueous (octanol) phases. Fewer hydrogen bonding and more carbon: ratio of polar: non-polar atoms. Lipid solubility and permeability to bbb is generally correlated: notable exceptions. Many other transporters/pumps: pgp, abcg2/bcrp (breast cancer resistant protein, mrp (multi-drug resistance-associated protein)
