Question 1

Long-term use of a receptor agonist can lead to:&#10;A) Adaptation of the post-synaptic neuron yielding creation of less receptor density (desensitization)&#10;B) Adaptation of the post-synaptic neuron yielding increased cell messenger production&#10;C) Down regulation yielding less synaptic neurotransmitter.&#10;D) A, B, and C&#10;E) A and B

Accepted Answer

Desensitization can occur with chronic stimulation. Two methods are known. Decreased receptor density, as well as changes in the cell physiology such that the messenger complex is more efficient.

Question 2

After the neurotransmitter serotonin attaches to a post-synaptic receptor, it:&#10;A) Releases and is then destroyed by proteases&#10;B) Spontaneously degrades&#10;C) It is taken back up into the pre-synaptic neuron&#10;D) It is taken up by the post-synaptic neuron&#10;E) Is metabolized by acetylcholinesterase

Accepted Answer

Serotonin is recycled via a re-uptake mechanism, where it is taken back into the pre-synaptic terminal and readied for reuse. There is also a small amount of diffusion into the area surrounding the synapse, the neurotransmitter being ultimately taken into glial cells.

Question 3

A GABA agonist will result in:&#10;A) Hyperpolarization of post-synaptic neurons&#10;B) The same effect as that of glutamine&#10;C) Decreased seizure threshold&#10;D) Decreased neurotransmitter destruction&#10;E) Decreased chloride ion influx

Accepted Answer

Through hyperpolarization of post-synaptic neurons, action potential frequency is decreased.

Deck 27: Introduction to the Central Nervous System