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

Do these two sentences mean the same thing?

Options are:
(1). no
(2). yes
(1).