Final answer:
When MAO is blocked by MAO inhibitors, the amine that is affected (levels rise) is tyramine.
Step-by-step explanation:
When MAO (monoamine oxidase) is blocked by MAO inhibitors, the amine that is affected and its levels rise is tyramine. MAO inhibitors block the action of the enzyme MAO, which is responsible for breaking down tyramine in the body. As a result, tyramine levels increase leading to potential side effects such as increased blood pressure.