Concept #1: Drugs & Toxins Affecting GPCR Signaling

Example #1: What is the effect of these toxins on the intracellular concentration of cAMP?

Practice: Cholera toxin increases the cellular cAMP levels by:

Practice: Pertussis toxin is produced by Bordetella pertussis, the bacterium that causes whooping cough. Pertussis toxin catalyzes the addition of ADP-ribose to Gi which ‘locks’ it in the GDP-bound state. If the uninhibited, toxin free GPCR pathway normally results in decreased glycogen synthesis, then what would be the effect of pertussis toxin?

Concept #2: Agonists vs. Antagonists

Practice: Caffeine is a molecule that binds to ______________ receptors, inhibiting their response.

Practice: Caffeine is a(n) __________ of adenosine that blocks its receptors from activation.