Depolarizing and hyperpolarizing receptor potentials in the non-myelinated nerve terminal in pacinian corpuscles.

1. Pacinian corpuscles or non-myelinated nerve terminals in Pacinian corpuscles, from which lamellae had been removed, were stimulated with linearly increasing compression of varying rate, which decayed linearly after a maximum compression.2. An impulse was initiated with a compression having a rate of increase greater than a critical slope. The critical slope was 1.1-1.2 rheobase/msec in both intact corpuscles and decapsulated terminals.3. The receptor potential of the terminal increased in magnitude and rate of rise with an increase in the rate of compression. Its rate of rise was linearly related to the rate of compression.4. Hyperpolarization was observed on removal of compression, and an impulse was initiated upon recovery of the hyperpolarized membrane potential.5. In some corpuscles or decapsulated terminals hyperpolarization was produced on compression and a depolarizing response was produced upon removal of compression. After rotation by 90 degrees along their long axis, they produced depolarization on compression.6. Difference in the directional sensitivity of corpuscles and decapsulated terminals was confirmed and was explained on the basis of the shape of the terminal.7. On- and off-responses of variable latency recorded from a central portion of the axon to Pacinian corpuscles were explained by the depolarizing and hyperpolarizing responses in the terminal.