Ionotropic Receptor

• Receptor contains an ion channel (binding site on a receptor) that opens or closes when neurotransmitter (NT) attaches to its binding site

• Example: door to your house (ionotropic receptor) has a key slot (binding site on the receptor) that opens when you put in and turn the key (neurotransmitter)

Metabotropic Receptor

• Receptor doesn’t contain an ion channel

• When neurotransmitter attaches to binding site, a G-protein changes

• Altered G-protein can affect near by ion channels

• Altered G-proteins also can activate enzymes, which create “second messengers”

• Second messengers: 1) affect near by ion channels and/or 2) activate DNA to perform other cellular functions

• Example: putting a key (neurotransmitter) into a key slot (binding site on the receptor) causes a near by elevator to turn on and open it’s doors (G-protein or second messenger opens near by ion channel) and sends a message that the elevator is operating to a control center elsewhere in the building (G-protein affects other cellular processes)