Pharmacology All 5–HT receptors are heptahelical serpentine receptors EXCEPT : A 5–HT1 B 5–HT2 C 5–HT3 D 5–HT4 💡 Explanation All 5–HT receptors are heptahelical serpentine receptors EXCEPT : ✓ Correct Answer: C. 5–HT3