Normally, the sensory neurone is at its resting potential. The axon membrane is negative on the inside.When pressure is applied to the Pacinian corpuscle, the membrane of the neurone stretches and a stretch-mediated sodium ion channel changes shape and widens to allow the diffusion of sodium ions into the neurone.The potential of the neurone changes and it becomes depolarised resulting in a generator potential which then creates an action potential (electrical impulse) that passes along the neurone.