What are the main features of an electrical synapse?
Direct contact between the interior of cells, allows sharing of cellular contents leading to electrical coupling, rapid signalling, small synaptic cleft, don't allow for inversion of the signal.
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What are the types of chemical neurotransmitters? Give an example for each.
Small molecule neurotransmitters (5-HT, DOPA, ACh, NA), peptide neurotransmitters (e.g. opioids, substance P) and others (metal ions and gases such as NO)
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What are the purposes of a chemical synapse?
Information transfer between cells, amplification of signals, integration of multiple inputs, modulation, inhibition and plasticity in learning and memory.
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What's different about NO as a neurotransmitter?
It is not stored and generated as required. It can get through cell membranes to act intracellularly and its action is not restricted to the synaptic cleft so it can affect adjacent cells.
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What type of vesicles store small molecules and peptides?
Small molecules are stored in clear vesicles and peptides in dense core vesicles.
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How is dopamine synthesised from tyrosine?
Tyrosine is converted by tyrosine hydroxylase (rate limiting step) to DOPA which is converted by DOPA decarboxylase to dopamine. This is packaged into vesicles by VMAT.
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How are peptide neurotransmitters synthesised?
Synthesised from pre-proproteins by converting enzymes. Post-translationally modified (usually cleaved) to form a smaller transmitter. Packaged into vesicles and transorted via axonal transport.
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Explain Ca dependent vesicular release.
Depolarisation causes voltage gated Ca channels to open. Ca binds to the SNARE protein causing it to bind with the vesicle and bring the vesicle to the plasma membrane to begin exocytosis.
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Give an example of fast activity regulation.
Binding of ACh to the nicotinic acetylcholine receptor. Binding to an ionotropic receptor requires no amplification steps.
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Give an example of slow activty regulation.
ACh binding to the muscarinic acetycholine receptor. Binding to a metabotropic receptor requires amplification steps e.g. a second messenger.
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What is an EPSP?
A depolarisation of membrane potential that requires an influx of posiive ions and increases firing rate.
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What is an IPSP?
A hyperpolarisation of membrane potential that causes an influx of negative ions or an efflux of positive ions and decreases the firing rate.
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Other cards in this set
Card 2
Front
What are the main features of an electrical synapse?
Back
Direct contact between the interior of cells, allows sharing of cellular contents leading to electrical coupling, rapid signalling, small synaptic cleft, don't allow for inversion of the signal.
Card 3
Front
What are the types of chemical neurotransmitters? Give an example for each.
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