This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
The skeletal muscles relaxant causing significant release of histamine is: 
Select and explain. 
A. Pancuronium., B. Atracurium., C. Gallamine., D. D-tubocurarine.
D: D-tubocurarine.
Answer: D: D-tubocurarine. 
Explanation: Due to its bulky cationic nature of d-tubocurarine it has a direct action on the mast cell that promotes release of histamine. Certain responses to tubocurarine like bronchospasm, hypotension, and excessive bronchial and salivary secretion appear to be histamine mediated. Atracurium, gallamine and pancuronium have less tendency to cause histamine release.