Locks and keys: receptor specificity, agonists and antagonists
Explains why each transmitter affects only its own receptors — and how drugs copy or jam the key.
Where this fitsConnects to 1 · Unlocks 2
- Connects to
- The synapse: release, binding and termination — This zooms into step 4 of the synapse: binding.
- Unlocks
- Fast doors and slow keypads: ionotropic and metabotropic receptors — Next: what happens after the lock turns — doors versus keypads.
- Dopamine: receptor families, clearance and pathways — Antipsychotics are D2 antagonists — keys that jam the lock.
Orient
Receptors are like locks. Unlocking the receptor = changing electrical potential of post-synaptic neuron (either excitatory or inhibitory). Neurotransmitters are like keys. Not all neurotransmitters bind to all receptors: specific receptors for specific NTs — serotonin binds to serotonin receptors, but not dopamine receptors. Drugs can mimic the key (agonist) or block the lock (antagonist).
Course terms
Your professor's wording, word for word from the slides. Learn the term and this definition — the explanation underneath is only there to help it make sense.
- Receptor (lock)
“Receptors are like locks. Unlocking the receptor = changing electrical potential of post-synaptic neuron (either excitatory or inhibitory)”Slides 02, p. 21
Binding changes the next neuron's electrical state.
- Neurotransmitter (key)
“Neurotransmitters are like keys. They unlock the receptor locks.”Slides 02, p. 21
The endogenous key.
- Receptor specificity
“Not all neurotransmitters bind to all receptors. Specific receptors for specific NTs.”Slides 02, p. 21
Serotonin binds to serotonin receptors, but not dopamine receptors.
- Agonist
“Drug binds to receptor and acts similarly to (mimics) endogenous neurotransmitter”Slides 05, p. 9
A copied key that turns the lock.
- Antagonist
“Drug binds to and blocks receptor preventing endogenous neurotransmitter (and agonist drugs!) from binding entirely or activating fully”Slides 05, p. 13
A key that fits but doesn't turn — it jams the lock.
From your course: Course slides 02, p. 21 · Course slides 03, p. 3
Tip: the ← and → keys move through the lesson.
Full lesson: Reversible receptor binding