This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Smooth Muscle, Subject name: Physiology
[{'content': 'Regulation of smooth muscle tone is persistently influenced by: \nSelect and explain. \nA. Calcium release from sarcoplasmic reticulum, B. Beta 1 receptor, C. Latch bridge mechanism, D. Troponin', 'role': 'user'}, {'content': "Answer: C \nExplanation: Latch bridge mechanism: - Once smooth muscle has developed full contraction, the amount of continuing excitation can usually be reduced to far less than the initial level even though the muscle maintains its full force of contraction. Fuher the energy consumed to maintain contraction is very less, This mechanism is k/a 'latch' mechanism. The impoance of latch mechanism is that it can maintain prolonged toxic contraction in smooth muscle,with little use of energy.", 'role': 'assistant'}]