for both facilitation and depression depends on changing of probability of neurotransmitter on time scale is observed as, facilitation reflects an increase in the probability of neurotransmitter release that lasts for up to hundreds of milliseconds and depression reflects a decrease in the probability of neurotransmitter release that persists for hundreds of milliseconds to seconds. and my question is that a prolonged exposure to neurotransmitter inactivates receptors on post-synaptic cell, how can we correlate these two phenomena. please help me.