Lecture 2 - Neurotransmitters Flashcards
Give some properties of neurotransmitters
- Small molecules
- Acetylcholine, Amines or Amino Acids
- Synthesized and stored at nerve terminals as small synaptic vesicles (SSVs)
- Usually released at synapses
- Bind to post-synaptic receptors
- Half-life ~ 5 msec
- Few (8 +)
Give some properties of neuropeptides
- Large molecules
- Synthesized in nerve cell bodies
- Stored in all parts of neurones as large dense-core vesicles (LDCVs)
- Released from dendrites & elsewhere
- Bind to distant receptors
- Half-life ~20 minutes
- Numerous (100+)
Synapses: what’s the difference between a LDCV (large dense core vesicles) and an SSV (small synaptic vesicles)?
Whereas SSVs contain classical neurotransmitters and activate ion channels, LDCVs contain neuropeptides and hormones which primarily activate G protein-coupled receptors (GPCRs)
What are the 3 main types of neurotransmitter?
amino acids, monoamines , and peptides
What effect does glutamate have on a receptor as a pose to GABA?
Glutamate – AMPA receptor -> influx of Na+-> Ca2+ influx -> depolarisation
GABA – AMPA receptor -> influx of Cl- -> hyperpolarisation -> inhibition
Where are the principle centres for noradrenergic neurones?
locus coeruleus and caudal raphe nuclei
What type of receptors are adrenergic receptors? What neurotransmitters act on them?
G-protein coupled
Catecholamines, especially noradrenaline and adrenaline
What are the 4 major dopaminergic pathways and their functions?
> > Tubero-infundibular pathway: transmits dopamine from the hypothalamus to the pituitary gland.
Mesocortical: Transmits dopamine from the VTA (ventral tegmental area) to the frontal cortex
Mesolimbic: Transmits dopamine from the VTA to the limbic system via the nucleus accumbens
Nigrostriatal: Transmits dopamine from the substantia nigra to the striatum. This pathway is associated with motor control.
What are the activities associated with
a) Tonic level dopamine function
b) Intermediate level DA function
c) Fast level DA function
which one is affected with Parkinsons?
> Tonic: Continuous - enabling of movement, cognition, motivation
Intermediate: Behaviour e.g. sleep and sex
Fast: Predictive of reward
Tonic
Why do seretonin drugs have side effects such as motor impairment?
Because seretonin is not just the happy transmitter - it also acts on the cerebellum for movement control.
What drugs act on the SERT receptor, which release 5-HT neurotransmitters that bind with 5-HT receptors?
Cocaine
Fluoxetine
Paroxetine
Sertraline
What is the precurser for 5-HT
What neuron produces it?
Tryptophan -> 5-hydroxytryptophan
5-hydroxytryptamine neuron
In cardiac tissue, acetylcholine has an ______ effect, which lowers/increases? HR. However it also behaves as an _____ neurotransmitter at neuromuscular junctions in skeletal muscle
In cardiac tissue, acetylcholine has an inhibitory effect, which lowers HR. However it also behaves as an excitatory neurotransmitter at neuromuscular junctions in skeletal muscle
CB1 is by far the most abundant _______ receptor with ___ transmembrane-spanning segments, and it is also expressed on peripheral neurons and other cell types. CB1 is negatively coupled to _____ and is either negatively or positively associated with selective ion channels. CB1 is expressed strongly in the _____, _____, and ______ which accounts for the well-known effects of cannabis on motor coordination and short-term-memory processing. Likewise, CB1 is expressed at ____ concentrations in the dorsal primary afferent spinal-cord regions, which are important in ____ pathways, whereas it is
expressed at low concentrations in the brainstem, which controls many ______ functions.
CB1 is by far the most abundant G-protein coupled receptor with seven transmembrane-spanning segments, and it is also expressed on peripheral neurons and other cell types. CB1 is negatively coupled to adenylate cyclase and is either negatively or positively associated with selective ion channels. CB1 is expressed strongly in the basal ganglia, cerebellum, and hippocampus which accounts for the well-known effects of cannabis on motor coordination and short-term-memory processing. Likewise, CB1 is expressed at high concentrations in the dorsal primary afferent spinal-cord regions, which are important in pain pathways, whereas it is
expressed at low concentrations in the brainstem,10 which controls many autonomic functions.
___________ - the main active compound from Cannabis sativa
9 tetrahydrocannabinol (THC) - the main active compound from Cannabis sativa
