1. Explain how the action of an inhibitory neurotransmitter might affect this synapse.
2. In certain diseases, the motor neurons are progressively damaged. Suggest two ways in which a person with such a disease may be affected.
An inhibitory neurotransmitter will not bind to the ligand-gated ion channels in the post-synaptic membrane. The effect would be that the following neuron or muscle cell woud not be activated and therefore the action potential would stop at the pre-synaptic membrane.
If a motor neuron is damaged (e.g. the resting membrane potential is disrupted) then either the membrane potential would polarize even more and the threshold of the voltage-gated ion channels would not be easily reached, causing the inability to move muscles, muscle paralysis. If the resting potential was too high, residing over the threshold, there would be uncontrolled action potentials pulsing from the motor nueron and the muscle cells would uncontrollably contract. A less severe effect is that it would be easier to fire off an action potential if the resting membrane potential depolarized only a little bit and still resided lower than the threshold.
Source: Campbell Biology Seventh Edition AP Edition