Author Question: Describe the structural basis of the blood-brain barrier and list two characteristics of a drug that ... (Read 73 times)

asmith134 · **on:** Jun 22, 2018

Describe the structural basis of the blood-brain barrier and list two characteristics of a drug that would allow it to pass through the BBB.

What will be an ideal response?

Question 2

What are two reasons that the relative concentrations of a psychoactive drug may be lower in an expectant mother's brain than in her fetus' brain?

What will be an ideal response?

kswal303 · **Reply #1 on:** Jun 22, 2018

Answer to Question 1

The cells comprising the capillaries that provide blood to the brain are tightly packed together, with minimal pores between them. In addition, parts of glial cells may cover the outside of the capillaries. These comprise a lipid barrier through which non-lipid soluble drugs cannot pass, unless the molecules are compatible with transport proteins that can carry them across these membranes. Thus, in order to penetrate this barrier, the molecule must be small and nonionized, e.g., like alcohol or lipid soluble or possess a structure allowing it to bind to a transport protein to be carried across these lipid membranes.

Answer to Question 2

The fetus has greater blood flow to brain than in the mother, has a poorly developed bloodbrain barrier, has poorly developed P450 enzyme system to metabolize drugs, and poorly developed kidney system for eliminating drugs from the body