Receptors and modes of cellular communication Flashcards
What are the 4 main ‘super families’ of receptors?
Ligand- gated ion channels, G-protein coupled receptors, Kinase-linked receptors, Nuclear Receptors
What is an example of a Ligand-gated ion channel?
Nicotinic ACh receptor
What is an example of G-protein coupled receptor?
Muscarinic ACh receptor
What is an example of a Kinase-linked receptor?
Cytokine receptors
What is an example of a Nuclear receptor?
Oestrogen receptor , steriod receptor
What is the time scale for each receptor in the 4 super families?
Ligand- Milliseconds
G-protein- Seconds
Kinase-linked- Hours
Nuclear- Hours
What is an endogenous agonist?
Compound naturally produced by the body which binds to and activates that receptor
What is an endogenous ligand?
Naturally occurring small molecules that bind to receptors- neurotransmitters, hormones, growth factors
What is the structure of a ligand-gated ion channel?
Ion channel with multiple protein subunits
Activation of GalphaS coupled receptors results in an inhibition of adenylyl cyclase. T or F?
False
Endocrine regulation requires release of hormones into what system?
Circulatory system
Adrenaline is a (1) if released during synaptic transmission and a
(2) if released into blood circulation.
1) Neurotransmitter
2) Hormone
Somatostatin release from D cells binding to somatostatin receptor on D cells is example of what cellular communication?
Autocrine
What is paracrine regulation?
Where signalling molecules are secreted into the extracellular space and bind to receptors located on adjacent cells, without passing through the circulatory system
What are 4 modes of cell communication?
Autocrine, Paracrine, Endocrine, Synaptic Transmission
What mode of cell communication acts as a negative feedback loop?
Autocrine
Parasympathetic and sympathetic responses both maintain the body’s homeostasis but what are the differences?
Parasympathetic- Returning body to routine
Sympathetic- Involved in preparing the body for stress-related activities
What do enterochromaffin cells secrete?
Histamine
What is the difference between Paracrine and Endocrine regulation?
Endocrine requires the circulatory system.
Paracrine- Cells are regulating or communicating with cells next door
What area is synaptic transmission specific to?
The Nervous System
What is a neurotransmitter?
Chemical substance released from a neuron and bringing about the transfer of an impulse to another neuron
Why can some neurotransmitters be hormones?
Depends on mode of communication
Examples of neurotransmitters
Acetylcholine, Adrenaline, Dopamine, Histamine
Salbutonal activates what type of receptors that results in brochodilation?
beta2 adrenoreceptors
G-protein receptors consist of how many loops in their structure? What nucleotides bind to them when they are active and inactive?
7
Active- GTP
Inactive- GDP
GPCRs are heterotrimeric (three different subunits), what are they and what 2 are attached to the plasma membrane by lipid anchors?
Alpha, beta, gamma
Alpha and gamma are attached to plasma membrane
When a signalling molecule binds to GPCR what do the two protein subunits consist of when they dissaccociate?
GTP- alpha subunit
beta-gamma dimer
What is a common enzyme activated by G-proteins that goes on to catalyze of synthesis of cAMP from ATP which is involved in responses to sensory input, hormones, nerve transmission etc.
Adenylyl cyclase
