Neurotransmitters (big ppt) Flashcards
What are 3 fast acting neurotransmitters and are they inhibitory or excitatory?
- Acetylcholine (Ach) - Excitatory in skeletal muscle and inhibitory at the heart
- Glutamate - excitatory
- GABA - inhibitory
What are neuromodulators?
- Cause a change in synaptic membrane that’s longer lasting
- Tend to be slower events e.g. learning, development
- Dopamine, Noradrenaline, Serotonin
What are ionotropic receptors?
- Membrane spanning ion channel proteins
- Excitatory or inhibitory
- Open directly in response to ligand (ion) banding
- Undergo change in shape when neurotransmitter binds
- Produce quick physiological responses
What are metabotropic receptors?
- Not ion channels but trigger signalling pathways and can affect the ion channel opening
- Excitatory or inhibitory
- Tend to involve second messenger
What system is Ach major neurotransmitter?
PNS and acts at neuromuscular junctions (NMJ)
What are neurons said to be called if they release Ach?
Cholinergic neurons
How is Ach broken down?
- Broken down by: acetylcholinesterase
- Into: choline and acetate
- Choline is transported back to presynaptic axon terminal to be reused
What are the 2 types of Ach receptors?
- Nicotinic receptors
- Muscarinic receptors
Where are nicotinic receptors found?
- Found in NMJ
- Respond to Ach AND nicotine
What do nicotinic receptors contain?
- Ion channels that open in response to Ach, resulting in depolarisation of target cell
What are nicotinic receptors in the brain important for (function)?
- Cognitive function
- Behaviour
What do muscarinic receptors couple with?
G proteins
Where are muscarinic receptors present?
- In the brain
- Present where PNS innervates peripheral glands/organs (e.g. salivary glands)
How do muscarinic receptors work?
Not ion channel; instead trigger signalling pathways in the target cell that inhibit action potentials
Where is noradrenaline a transmitter?
Peripheral heart and CNS
