This is due to the reduction of excitatory synaptic transmission in a nucleus and increased excitability in motor neurons caused by nicotinic activation .
This is due to the reduction of nicotine transmission in a nucleus and an increased excitability in motor neurons caused by excitatory synaptic activation .

Are these two sentences paraphrases of each other?
Choose from:
[I] no.
[II] yes.
[I]