Norepinephrine and epinephrine can have either excitatory or inhibitory effects on target organs.

• A. True
• B. False

Answer: (A)

Verified step by step guidance

1. Understand the role of norepinephrine and epinephrine: These are catecholamines that function as neurotransmitters and hormones, primarily involved in the body's 'fight or flight' response.
2. Identify the receptors involved: Norepinephrine and epinephrine bind to adrenergic receptors, which are divided into alpha and beta types. Each type can have different effects on target organs.
3. Explore the effects on different organs: Depending on the receptor type and location, norepinephrine and epinephrine can cause either excitatory or inhibitory effects. For example, they can increase heart rate (excitatory) or relax airway muscles (inhibitory).
4. Consider the physiological context: The overall effect of these neurotransmitters can vary based on the physiological state of the body and the specific organ system involved.
5. Conclude based on receptor interaction: Since norepinephrine and epinephrine can interact with multiple receptor types, they can indeed have both excitatory and inhibitory effects on different target organs, supporting the statement as true.