From Leipzig to London
Katz obtained his medical degree in Leipzig in 1934 and left Germany in 1935 to work with A. V. Hill at UCL. In 1939 he joined John Eccles and Stephen Kuffler in Sydney to study neuromuscular transmission. After returning to London, he became professor of biophysics in 1952.
References: [1]
Small signals without stimulation
Using intracellular microelectrodes, Katz and Paul Fatt recorded end-plate potentials at the frog neuromuscular junction. In 1952 they described small spontaneous depolarizations even without stimulation of the motor nerve: miniature end-plate potentials. They related these events to spontaneous acetylcholine release from the nerve terminal.
References: [3]
Inferring packets from response fluctuations
In 1954 Katz and José del Castillo analyzed response fluctuations under conditions including reduced calcium. Larger responses behaved as combinations of small units, with occasional failures after stimulation. Their statistical distributions supported release in discrete packets. “Quantal” here describes release units, rather than a quantum-mechanical explanation.
References: [3]
Release probability and synaptic mechanisms
The analysis also connected calcium with the probability that a release unit would occur. Electrical signals in muscle could therefore probe processes in the presynaptic terminal. The shared 1970 prize concerned transmitter storage, release and inactivation; Katz’s work focused on transmission and release mechanisms.