Impulse-transmitting cell (6)
I believe the answer is:
neuron
'impulse-transmitting cell' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for neuron that I've seen before include "Conductor" , "Transmitter of nerve impulses" , "Impulsive thing" , "Nerve impulse cell" , "It transmits nerve impulses" .)