| Abstract: | A simple model is proposed, whereby a single buffering system for intracellular calcium accounts for the steep external Ca dependence of neurotransmitter release during depolarization of the presynaptic nerve terminal. Ca entry and buffering in the nerve terminal are assumed to be saturable; release is assumed to be proportional to intracellular Ca. The novel feature of this model is that it explains the apparent cooperative relationship between transmitter release and extracellular calcium, without invoking cooperative Ca binding. |
