Muscarine-sensitive voltage-dependent potassium current in cultured murine spinal cord neurons.

Muscarine produced membrane depolarization and decreased membrane conductance of mouse spinal cord neurons in dissociated cell culture. When the neurons were voltage clamped, muscarine evoked inward currents which increased with membrane depolarization and decreased with membrane hyperpolarization. However, the muscarine-induced inward currents did not invert at large negative potentials, suggesting that muscarine decreased a voltage-dependent potassium current (m-current) [2]. Using the voltage-jump current-relaxation technique, m-current was demonstrated in spinal cord neurons and shown to be a muscarine-sensitive potassium current.