Neurotransmitters Flashcards
(27 cards)
What is the dendritic spine?
The point of communication at the molecular level – can be thousands per neuron.
What was the first experimental proof of chemical transmission?
Someone took an isolated frogs heart and stimulated the vagus nerve to induce contraction.
Then soaked another heart in the solution from the first – it contracted.
Therefore the contraction released chemicals
What are neurotransmitters?
Endogenous chemicals which transmit signals from a neurone to a target cell across a synapse.
What are the two types of chemical synapse?
Axodendritic
Neuromuscular
What is an axodendritic synapse?
Axon to dendrite
What is a neuromuscular synapse?
Nerve ending to skeletal muscle cell
True or false:
A given synapse can utilise multiple small molecules
False. Only one
Examples of small molecules
Ach, Glutamate, Aspartate, GABA, ATP, Dopamine, Norepinephrine, Epinephrine, 5HT and Histamine.
What 5 criteria define a “classical” neurotransmitter?
Synthesis - enzymes must be present presynaptically
Storage - specific storage in secretory vesicles
Release - spatial/chemical control release into synapse
Reception - has receptors
Removals - must be able to be terminated
Where are cholinergic synapses present?
Frontal lobe and the sympathetic/parasympathetic nervous system
What receptors does acetyl choline act on?
Cholinergic
Nicotinic and muscarin
What is ChAT?
Choline acetyltransferase
Catalyses synthesis of acetylcholine
Choline is serum devised – needs to be delivered
What is AChE?
Acetylcholinesterase
Breaks acetylcholine into choline which is transported back into the neuron and acetyl
Inhibitors of this are used to treat Alzeimer’s
How is glutamate generated?
Glutamine is converted to glutamate by glutaminase
Glutaminase sits on the mitochondrial membrane
Actions of the glutamatergic synapse
Glutamate generated
Packaged into vesicles
Reuptake by enzymes
Converted into glutamine
There is a close metabolic relationship between glutamate and _, dependent on the enzyme _
GABA
Glutamic acid decarboxylase, GAD
What does Glutathione do?
Protects from free radical damage
GABAergic synapses require _
GAD
It is localised to distinct regions of the brain
How is GABA transmission terminated?
By GATs - transporters
Generation of Dopamine
- Made from tyrosine,
- Requires DOPA decarboxylase, but not Dopamine β-hydrolase
Where does dopamine operate?
Exists in the basal ganglia, substantia nigra and the ventral tegmental area.
Substantia nigra contains neuromelanin and is lost first in Parkinsons, but contains significant redundancies, so can loose a lot.
Where is the key area of serotonin/5HT signalling?
The Raphe nuclei
Generation of 5HT
Tryptophan -> 5-hydroxytryptophan -> serotonin
