1.3.1 CNS Neurotransmitters Flashcards
Describe the synthesis of serotonin.
– made from tryptophan → 5-HT
Some drugs can do what to histamine receptors?
-Inhibition of histaminergic receptors is responsible fro the sedative adverse effects of many drugs
What is the synthesis of Dopamine?
tyrosine → DOPA → Dopamine
What is the synthesis of Norepinephrine?
from tyrosine → DOPA → dopamine → NE → Epi
What are some examples of indirect gating?
- Gs: stimulates AC
- Gi: inhibits AC & opens K channel
- Gq: stimulates phospholipase C
- Go: closes Ca channel
What are the characteristics of chemical synapses?
- Slower and more complex signaling than electrical synapses
- Important for the function of most CNS active drugs
What is the importance of glutamate?
most predominant excitatory NT in CNS
Drugs that target opoid receptors are used for?
-Drugs targeting opioid receptors are used to treat pain
What are the receptors for glutamate?
NMDA (blocked by Mg)
AMPA (pain)
kainate
GPCR
Describe the synthesis of GABA.
-Formed by decarboxylation of glutamate
What is indirect gating in regards to chemical synapses?
- Indirect Gating: Non-Channel Linked Receptors
- Binding of nt activates second messenger pathways via G-proteins (metabotropic)
How is acetylcholine synthesized?
- Combination of acetyl CoA (from mitochondria) and choline (from diet)
- Catalyzed by choline acetyltransferase (ChAT)
Describe the termination of GABA
Reuptake
How can stimulants and amphetamines affect the action of norepinephrine?
Amphetamines - can cause increased release of norepinephrine
Stimulants (cocaine) - cause decreased reuptake of norepinephrine
How is norepinephrine terminated?
Reuptake
What is the sequence of events in a chemical synapse?
- Release of NT from pre-synaptic terminal requires calcium
- Voltage-dep calcium channels open when AP depolarizes them
- Transmitter diffuses through synaptic cleft to post-synaptic neuron
- Post-synaptic response depends on the type of receptors present
What are the receptors for norepinephrine?
Adrenergic
α1-excitation, increased IP3:DAG
α2 – inhibitory at pre-synapse
β- GPCR (increased cAMP)
Alzheimers disease is related to cholinergic action?
- reduction in the activity of cholinergic neurons
- drugs are used in AD to increase cholinergic activity
What are the characteristics of nuclear receptors?
- Binding of a ligand to a nuclear receptor will cause a downstream change in gene expression
- This modulation of gene expression may be either to up or down regulate transcription
What is the role of serotonin?
- Serotonergic mechanisms modulate anger, aggression, body temp, mood, sleep, human sexuality, appetite and metabolism
- Also have potential to stimulate emesis
What are the receptors acetylcholine and what is their importance?
- Muscarinic – Metabotropic receptors important in glandular secretion (M1 is excitatory and M2 is inhibitory)
- Nicotinic – Ionotropic receptors important in motor end plate function (increased conductivity to cations)
How is the effect of acetylcholine terminated?
- Metabolism by acetylcholinesterase (AChe) on postsynaptic membrane (choline recylced)
- Very short half life
What are some examples of neurotransmitters that utilize direct gating?
- Glutamate
- ACh
- GABA
- Glycine
- Serotonin
What is the effect of serotonin on the different receptors? (Dont know if this is important)
- Receptors
- Metabotropic:
- 5-HT 1A– Inhibitory
- 5-HT 2A – Excitatory
- Ionotropic:
- 5-HT 3 – Excitatory
- ↑ cation conductance
- 5-HT 4 – Excitatory
- ↓K conductance
