1. Focal recordings from the mouse diaphragm nmj.
A. Recording site: an endplate stained with 2-Di-4-Asp. B. Examples of EPSCs recorded at physiological conditions (2 mM Ca2+) and at the reduced Ca2+ (0.5 mM). Recordings at 2 mM Ca2+ demonstrate multiquantal EPSCs followed by asynchronous quanta. Recordings at 0.5 mM Ca2+ demonstrate a unitary EPSC (top), a transmission failure followed by an asynchronous mEPSC (middle), and a double quantal EPSC (bottom).