Which channels are opened when a neurotransmitter binds on the post synaptic membrane in excitatory neurones?
And what does this cause?
Na in K out= depolarisation of the membrane
Which channels are opened when a neurotransmitter binds on the post synaptic membrane in inhibitory neurones?
And what does this cause?
Cl in = hyper polarisation of the membrane
Give an example of a glial cell:
Astrocyte
How do glial cells modulate the shape of post-synaptic response?
Remove the neurotransmitter from the synaptic cleft
Compare the following features of the Nervous system and Endocrine:
Mediator molecules
Cells affected
Time of onset of action
Duration of action
What criteria must a chemical meet before it can be called a neurotransmitter? (3)
Must be synthesised and stored within a pre-synaptic neurone (neurone must contain synthesising enzyme)
Stimulation causes release of the chemical from the nerve terminal (depolarisation)
Must cause the same effect as nerve stimulation on the postsynaptic neurone when applied directly onto the neurone
How many neuroactive substances can be found in the CNS?
Approx. 40
What type of channels are inotropic receptors?
Ligand-gated ion channels
What type of channels are metabotropic receptors?
GPCRs
List the (7) major CNS transmitters:
Glutamate
GABA
Acetylcholine
Monoamines (Noradrenaline, Dopamine & Serotonin)
Histamine
Opioids
Nitric Oxide (synthesised on demand & easily crosses the phospholipid bilayer -> its release is not Ca dependant but its synthesis is!)
What causes a neurotransmitter to have a dual response?
It acts on both Ionotropic receptors (faster inital response) AND metabotropic receptors (slower inital response because it takes a while for the second messenger to be synthesised)
What do neuromodulators do?
They alter the strength of response
What do neurotrophic factors do?
Influences neuronal differentiation and proliferation
(most do this by acting on Tyrosine kinase receptors)
What are the (4) different targets for drug action?
Ion channels
Receptors
Enzymes
Transporter proteins
Name an excitatory neurotransmitter in the CNS:
Glutamate
Name an inhibitory neurotransmitter in the CNS:
GABA
Which drug targets transmitter synthesis in the CNS?And what is the clinical application of this drug?
L- Dopa
Parkinson's disease
Which drug targets transmitter storage in the CNS?And what is the clinical application of this drug?
Reserpine
Hypertension
Which 2 drugs targets transmitter release in the CNS? And what is the clinical application of this drug?
Amphetamine
Na & Ca channel blockers
Attention Deficit Hyperactivitiy disorder (ADHD)
Name 2 receptor agonists in the CNS?
And what is the clinical application of this drug?
Morphine (analgesia)
Buspirone (Anxiety)
Name 2 receptor antagonists in the CNS?
And what is the clinical application of this drug?
Cloazapine (antipsycotic)
Memantine (alzheimers)
Which 2 drug target reuptake in the CNS?
And what is the clinical application of this drug?
Cocaine (stimulant)
Fluoxetine (depression)
Which 2 drugs target degradation in the CNS?
And what is the clinical application of this drug?
Moclobemide (depression)
Donepezil (alzheimers)
Which drug targets intracellular signalling in the CNS?And what is the clinical application of this drug?
Lithium
Bipolar disorder
Which drug targets nerve growth in the CNS?
And what is the clinical application of this drug?
Myotrophin
Motor neurone disease
Why is it not a good idea to completely 'knock out' a neurotransmitter?
Give an example:
Bad side effects -> widely spread
e.g. Completely knock out glutamate = coma
Name 2 examples of drugs that target Glutamate:
(include their clinical use)
Ketamine = NMDA channel blocker (one of the inotropic receptors of Glutamate) => dissociative anaesthetic
Memantine = NMDA receptor antagonist => cognitive enhancer (in alzheimers)
What may drugs that target glutamate be used to treat? (4)
Learning and memory
Schizophrenia
Mood disorders
Excitotoxicity
Name the key 2 examples of drugs that target GABA: What are their clinical uses?
Benzodiazepines: Sedative hypnotic
Barbituates: Sedative hypnotic
Others:
Vigabatrine: GABA transaminase inhibitor = anti-epileptic
Alphaxalone: steroid general anaesthetic
Baclophen: GABA B angonist = spascticity
GHB: drug of abuse
In which (3) illnesses are GABA B recreptors for GABA targetted?
Epilepsy
Anaesthesia
Cerebral Palsy
