Presynaptic facilitation is caused by: (A) Prolonged opening of calcium channels, (B) Prolonged opening of chloride channels, (C) Prolonged opening of sodium channels, (D) Prolonged closure of potassium channels
Answer is A. Presynaptic facilitation: when a third neuron facilitates the presynaptic neuron at it ternimal end is called presynaptic facilitation It causes increased neurotransmitters by opening ca+ channals Ref:Guyton and Hall textbook of medical physiology 12th edition,page number:675,676,677