Intro to Cell Signalling Flashcards
What is a synapse?
Communication/gap between cells
Give an example of a signalling molecule and its different responses
AcetylCholine (AcH)
- works via receptors on salivary glands to increase saliva
release
- works on heart muscles to decrease contraction force
- increases skeletal muscle contraction
What is the role of Pumps and exchangers?
Set up gradients that are exploited by ion channels
How do synapses enable cell signalling?
Cells release chemicals across a synapse, causing an effect on the post synaptic membrane
What types of transporters aid cellular control?
- exchangers
- symporters
- antiporters
Name some examples of Ion channels
- Na+
- Ca2+
- Mg2+
etc.
What are the 2 major Ion Channels involved in intracellular signalling?
Voltage Gated Ion Channels
Ligand Gated Ion Channels
What is the significance of transporters?
Important for bringing charged molecules into cells
Outline the mechanism of maintaing Ca2+ levels in cytoplasm
- Na+/Ca2+ exchanger in heart active after every
heartbeat - Ca2+ pump in organelles and cell membranes
- Ca2+ uptake in mitochondria through importer
- Ca2+ pump in ER
What are the 2 types of synapses?
- Electrical
- Chemical
When can transporter mechanisms go wrong?
In disease states e.g. heart failure
How do enzymes aid signalling to cells?
Work on specific amino acids on specific proteins
Explain what is meant by an electrical synapse?
Cells connected by a connection that doesn't impede electrical flow (action potentials) e.g. - endothelial cells - cardiac muscles - epithelial cells
What alters the effect of AcH on different areas of the body?
Effect differs due to the different receptor mechanisms on the various forms of muscle
What is endocrine intracellular signalling?
Endocrine cells release signals/hormones affecting distant target cells via blood stream
How are voltage gated ion channels activated?
When depolarisation occurs, gated channels open causing an influx in ions
Name the different types of receptors involved in cellular control
- Ligand Gated Ion Channels (LIGC)
- G Protein Coupled Receptors (GPCR)
- Tyrosine Kinase Linked
- Nucleur
Why are signalling molecules so significant in the bodys physiology?
Signalling molecules ar eversatile and nduce differential responses
Name examples of common LIGC
- Neurotransmitter receptors (e.g. Na+/K+ + Glucose
co transport) - Ca2+ activated K+ channel
- Cyclic nucleotide gated channel (cAMP activated)
What is a chemical synapse?
One cell releasing chemicals onto another cell via GPCR or LGIC
e.g.
- neurons; precursors made and stored in vesicles to be
released
What is the normal membrane potential?
-60mV
How are Ion channels regulated in the body?
Activated by stimuli and controlled by concentration gradients
Name some enzymes involved in signalling
”- protein kinase A/G/C
- Phospholipase A/A2/C
- Cholinesterase (inhibited by donepezil tacrine)
- Adenylate Cyclase
- Phosphatidylinosito-3-kinase
- HMGCoA Reductase (inhibited by statins)
- Monoamine oxidase (inhibited by antidepressants)
What is a common use for Na+ channels?
Target for local anaesthetics (e.g. lignocaine, procalinamide)
How is the plasma membrane adapted for intracellular communication?
Plasma membrane contains proteinaceous pores
- pores present in all biological cell membranes
- controls flow of ions and molecules in/ out of cell
- aids cellular communications
What are the different types of intracellular signalling?
- Paracrine
- Endocrine
- Synaptic
What is a pharmacological use of Ca2+ channels?
Ca2+ channels are a common target for Dihydropyridines (e.g. nifedipine)
and Anti hypertensives
Which biological molecules act as major drug targets?
Receptors
Enzymes
Ion channels
Transporters
What is paracrine signalling?
When cells produce signals to induce changes in nearby cells
How are Cl- channels used in medicine?
Cl- channels are targeted by anti-arrhythmic agents (e.g. vernakalant)
