Neurotransmitters

What are the different neurotransmitters?  What class is each?  Which are the excitatory and inhibitory receptors of different neurotransmitters?  What compound might block a receptor?
a.    Acetylcholine

-Class: cholinergic

1. Nicotinic Receptors: Excitatory and can be blocked by curare blocks

2. Muscarinic: G-protein gated (opens K channels) and can be excitatory or inhibitory

-Example: can inhibit heart – basically slowing down heart rate

b. Monoamines

-Class: biogenic amines

1. Serotonin

-In CNS and PNS

-Excitatory: 5-HT2 (G-protein-gated) and 5-HT3 (Ligand-operated)

.G-protein-gated transmits signal to ligan and then Ligand channel regulates flow of ions across the cell

-Inhibitory: 5-HT1, basically a second messenger which can make synapses less likely to fire

-Emetic: can cause vomiting

2.Dopamine

-Excitatory: D1

-Inhibitory: D2

-Lack of dopamine can cause Parkinson

3. Norepinephrine

-Excitatory: a1, B1

.can increase heart rate

-inhibitory: B2

c. Amino Acids

-Class: Amino Acid Neurotransmitters

1. Excitatory: Glutamate and Aspartate

2. Inhibitory: GABA and Glycine (inhibits the muscle to do the opposite which allows you to actually move your muscle)

d. Peptides

-Class: Neuropeptides

1. Excitatory: Substance P-involved with pain

2. Inhibitory: Endorphins-similar to how euphoria blocks pain

e. Gases

-Class: Gasotransmitters

1. Excitatory: Nitric Oxide – involved inside cells during neural transmission

2. Inhibitory: carbon monoxide-influences neuronal activity and can cause muscles to relax

f. Lipids

-Class: Endocannabinoids

1.Inhibitory: Retrograde inhibitor from postsynaptic to presynaptic

. Example: when THC binds to the CB1 receptor and causes relaxation and changes in appetite