Neuropeptides I Flashcards
What are neuropeptides?
small protein-like molecules (3 – 30 amino acids long) synthesised from larger precursors and used by neurones to communicate with each other.
WHat are neuropeptides synthesised from?
Larger peptides which are processed to create the final molecule
When was neuropeptide signalling established?
b4 small molecule transmitters
Emerged when the links between metabolism and cellular communication developed in complex organisms
Which organisms use neuropeptides a lot?
sea anemones, coral, jelly fish, Hydra
How many neuropeptides have eben identified in the mammalian brain?
> 100
How are there more functional peptides than precursors?
Individual precursors can give rise to more than one neuropeptide
Significance of one precursor giving rise to more than one neuropeptide?
Gives diversity as a precursor in one cell can give rise to more than one species
Difficulty of defining smthn as a neurohormone or neuropeptide?
They can have different effects elsewhere as well as a neuronal effect
Where do oxytocin and vasopressni act?
GI tract as well as neurons
What do neuropeptides act at?
GPCRs
What can neuropeptides affect?
Neuronal communication
WHich brain functions are neuropeptides involved in?
Analgesia, reward, food intake, learning, memory
Where are neuropeptides synthesised?
Cell soma
What are neuropeptides synthesised as?
Large precursor molecules
What are the neuropeptides transported to their release sites in?
Dense core vesicles
Speed of neuropeptides effects?
Slower modulatory effects instead of fast signalling
What terminates the action of neuropeptides?
Extracellular proteases
Where are the proteases for neuropeptides?
Membrane associated
Are neuropeptides reuptaken/recycled?
No
What are neuropeptides coreleased with?
Classical transmitters
How are neuropeptides coreleased with classical transmitters?
In diff vesicles, released from the same site as a result of the same stimulations
When does the initial processing of neuropeptides occur?
During the trafficking in the transgolgi network
What happens to neuropeptides while they are being transported in the vesicle from the soma to the nerve terminal?
Still being modified
Distance between soma and terminal is v far in some neurons–> opportunity for processing during the journey
Conc of neuropeptide in their vesicles?
10mM (lower than classical transmitters (ab 100mM))
