Download Transmitters

TRANSMITTERS
a. Ionotropic (channel-linked) receptors:
transmitter binds to binding site at ion
channel (receptor coupled to channel)
b. Metabotropic (G-protein linked) receptors:
1. Receptor activates G-protein » alpha subunit
splits off » binds to ion channel.
2. Receptor activates G-protein » alpha subunit
splits off » activates enzyme » enzyme produces
2nd messenger (e.g. cAMP) » 2nd messenger
changes ion channel ( more common )
Metabotropic (G-protein linked):
TRANSMITTERS
Acetylcholine (ACh): - nicotinic receptor (ionotropic)
- muscarinic receptor (metabotropic)
AChE= acetylcholine esterase
Monoamines: - DA, NE, E » catecholamines
- Serotonin (5-HT) » indolamine
- Monoamine oxidase (MAO)
- 5 DA receptors » all metabotropic
- D1 » increases cAMP (2nd messenger)
- D2 » decreases cAMP
- 4 NE receptors » all metabotropic (cAMP)
- œ1, œ2, ß1, ß2
- 7 5-HT receptors » 6 metabotropic
cAMP= cyclic adenosine monophosphate
TRANSMITTERS
Amino acids:
Glutamate » NMDA, AMPA, Kainate -ionotropic
Metabotropic 1 or 2
Glycine
GABA a,b
a=ionotropic, b=metabotropic.
GABA a » 3 subtypes
- affinity for GABA only
- GABA + benzodiazepines
- GABA + barbiturates +ETOH
Neuropeptides » Enkephalins, Endorphins, etc.
Nitric oxide (NO) - retrograde messenger
from Pinel text
L-DOPA
PCPA-5HT; (tryptophan)
Physostigmine - AChE
Reserpine-5HT
Amphet, Cocaine - DA
Cocaine - DA
Amphet-NE, Morph-End
Prozac - 5HT
Botulinum toxin - ACh
Apomorphine - DA
Atropine,curare » Ach
Thorazine - DA (antipsychotic)