Slow-adapting impulses were recorded from the single nerve fiber innervating the Pacinian corpuscle of the cat planta, which was stimulated by constant pressure. Slow-adapting Pacinian corpuscles responded to both low-frequency (0.1-0.01 Hz) and high-frequency (400–800 Hz) vibrations. Simultaneously performed electron microscopy showed that there were no definite ultrastructural differences between slow- and fast-adapting Pacinian corpuscles.