Neurotransmitters

Question 1

Define: Neurotransmitter

Answer 1

A neurotransmitter is any chemical that diffuses across a neural synapse, binds to receptors on a postsynaptic neuron, and causes changes in the cell’s composition (affects its function or products), and/or the behavior of the cell.

There are two types of neurotransmitters: i) excitatory and ii) inhibitory.

Question 2

Define: an Inhibitory Neurotransmitter

Answer 2

An inhibitory neurotransmitter makes the postsynaptic neuron LESS likely to fire and propagate an action potential (the electrical impulse that allows nerve communication).

Question 3

Define: an Excitatory Neurotransmitter

Answer 3

An excitatory neurotransmitter makes the postsynaptic neuron MORE likely to fire and propagate an action potential.

Question 4

How many neurotransmitters have been identified in the human nervous system?

Answer 4

More than 60 (as of 2013).

Question 5

Describe the function of serotonin.

Answer 5

Serotonin is an inhibitory neurotransmitter involved in the regulation of mood, sleep, appetite, and memory.

It is derived from the amino acid tryptophan, and plays an important role in generalized positive emotion.

Question 6

Describe the function of dopamine.

Answer 6

Dopamine is an inhibitory neurotransmitter involved in mood, reward circuits, sleep, pleasure, and voluntary movement.

Dopamine plays a major role in the pathophysiology of Parkinson’s disease (decreased activity) and schizophrenia (increased activity).