Neurotransmission Flashcards
How do neurones communicate
Electrical synapses- gap junctions
1 connexon=6 connexins
Bi directional flow
Chem synapses- uni directional- pre to post- synth, storage and release of NT
Outline classical neurotrasmitters eg Ach
Clasical- Acetylcholine- synth using Ach-transferase- storage in vesicles in pre, released by exocytosis, choline recycled by acetylcholinesterase
Describe the NT glutamate
Glutamine converted to glutamate by glutaminase
Packed into vesicles by vesicular transporter
Released by exocytosis
Taken up by glutamate transporter on glial cell
Converted to glutamine by glutamine synthetase
Enters pre by glutamine transporter
Describe the NT GABA
Glutamine to glutamate by glutaminase
Glutamate to GABA by glutamic acid decarboxylase
and pyridoxyl phosphate
Packed by vesicular transporter
Taken up by GABA transporter on glial cell
GABA to glutamate by GABA transaminase
glutamate to glutamine by glutamine synthetase
Transported to pre by glutamine transporter
List the two types of biogenic amines and name examples
indolamines- 5HT and catecholamines- DA, NA, A
Describe the formation of catecholamines
Tyrosine- tyrosine hydroxylase L dopa- DOPA decarboxylase Dopamine- Dopamine B-Hydroxlase Noradrenaline- Phenylethanolamine N-methyl-transferase Adrenaline
Describe the formation of 5-HT
Tryptophan- tryptophan hydroxylase
5-hydroxytryptophan (5HTP)- 5HTP decarboxylase
5-hydroxytryptamine (5-HT)
Terminated by MAO/COMT or reuptake
List the formation and features of NO- atypical neurotransmitter
L-arginine –> NO by NO synthase
- Not stored in vesicles
- Diffuses freely across membranes
- Bidirectional - retrograde messenger
- Not released by exocytosis
Describe ionotropic receptors/ligand gated ion channels
In PPBL
Channel closed, sig mol (ligand) binds to ec part of receptor
Conformational change due to activation, pore opens, ion moves through channel- gradient
Cellular response- fast- ms-s
Describe tyrosine kinase receptors
In plasma membrane Receptor inactive, exists as monomers Ligand binds- form dimer Activation Phosphates bind- relay proteins attach to sites on activated receptor- multiple downstream events- slow
Describe nuclear receptors
eg PPAR
ligand binds to cytoplasmic receptor, messenger-receptor complex travels to nucleus, binds to receptor, form mRNA, cytoplasm- new protein formed- SLOW
Describe how drugs of abuse affect release
Amphetamine increases non exocytotic release of NA, DA
MDMA increases release of 5HT, DA, NA
Describe how Aricept is used to treat Alzheimers’
Block acetylcholinesterase
Increase cognitive function
How does anxiety and depression affect termination?
5HT isn’t reuptaken
Describe drugs used for the following diseases and the receptors they target: Pain Migraine Schizophrenia Anxiety Anaesthesia
Pain- opioids- mu opioid agonist
Migraine- triptans- 5HT1 agonist
Schizophrenia- anti psychotics- D2 antagonists
Anxiety- benzodiazepines- GABAA modulator
Anaesthetics- ketamine, PCP- NDMA antagonist
