When people get "hooked" on drug of abuse, the sequence of events often proceeds something like this: They take a dose that gives them their desired effect, then after a while that dose does not work anymore, so they up the dose. This cycle can continue for a while, but then they reach the point where if they skip a dose or try to quit, they experience severe withdrawal. Which of the following properties of signaling systems is most likely to explain this series of events?
A) up-regulation of receptors
B) down-regulation of receptors
C) competition
D) saturation

Question

Quizplus · Accepted Answer

Down-regulation of receptors is when there is a decrease in the number of receptors on the surface of cells. With repeated exposure to a drug, the body may down-regulate receptors in an attempt to maintain homeostasis. This means that the same dose of the drug will no longer have the same effect, and the individual will need to take more to achieve the desired effect. However, if the individual skips a dose or tries to quit, there are now fewer receptors available to bind to the drug, which can lead to severe withdrawal symptoms.

When People Get "Hooked" on Drug of Abuse, the Sequence