Session 1 Flashcards
What are the 3 types of EXC signalling?
Paracrine- stimulating adjacent cells
Autocrine- stimulating self
Endocrine- releasing hormones directly into blood
What 3 things need to be regulated when it comes to hormones?
Synthesis, release and degradation
What are the 3 types of molecules a hormone can be?
Catecholamines (hydrophilic)
Peptides/proteins (Hydrophilic)
Steroids (lipophilic)
Explain the difference between catecholamines, peptides/proteins and steroids in terms of half life, action time and receptor locations
Catecholamines- half life= sec, action time=milliseconds, receptor location=plasma membrane.
P/P- mins, mins to hrs, plasma membrane
Steroids- Hrs, hrs to days, cytosolic/nuclear
How to catecholamines hormones work?
Causes change to membrane potential therefore triggering synthesis of cystolic 2nd messengers
How to Peptide/protein hormones work?
Triggers synthesis of cystolic 2nd messengers, which trigger protein kinase activity
How do steroid hormones work?
The receptor-hormone complexes control transcription and stability of mRNAs
Give an example of a paracrine signalling molecule
Neurotransmitter
Give examples of neurotransmitters (6)
Adrenaline Noradrenaline ACh Amino acids Monoamines Peptides
Which two types of extracellular signalling share signalling molecules?
Paracrine and autocrine signalling
What are the. Types of signalling molecules targets?
Receptors
Ion channel (ligand gated)
Transporters
Enzymes
(Remember: RITE)
What types of receptors can you get?
Kinase linked receptors
Ion channels (ligand gated)
Nuclear/intracellular
GPCR
How do kinase linked receptors act?
They work intracellularly by the phosphorylation of molecules causing signalling cascades
Give an example of a process that requires a kinase linked receptor
Gene transcription
What is another name for ligand gated ion channels?
Ionotropic receptors
What type of ligands are required for nuclear/intracellular receptors?
Lipid soluble ones
eg. steroid
What are the consequences of a ligand-nuclear receptor complex?
Complex migrates to nucleus, binds to transcription factors and (in/)activates a (set of) gene(s)
What are the 3 subtypes of GPCRs?
Gq, Gi, Gs
What is an example of a signalling molecule used as a ligand for kinase linked receptors?
Growth factor cytokines
What is an example of a signalling molecule used as a ligand for ligand gated ion channels?
Neurotransmitters ie ACh, NA
What is an example of a signalling molecule used as a ligand for nuclear/intracellular receptors?
Thyroid hormone, steroid, vitamin D
What is an example of a signalling molecule used as a ligand for GPCRs?
Hormones, opiates, ‘slow’ neurotransmitters
When would a transporter protein be needed?
When the molecule is extremely polar and/or going against its concentration gradient
Where might you find a transporter protein?
Presynaptic membranes
