Term
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Definition
•Fast ligand-gated channels
•Transmitter Gated Channel |
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Term
| Fast ligand-gated Channels |
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Definition
–Receptor and channel—same protein
–Action is direct
–Binding of ligand causes the channel to open or close
–Change in transport of ions through the channel causes the target response |
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Term
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Definition
| –nicotinic acetylcholine receptor (nAchR). |
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Term
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Definition
•Receptor and enzyme—same protein
•Ligand binding activates the enzyme
•Action is direct
•Activated enzyme causes the target response |
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Term
| Epidermal Growth factor receptor |
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Definition
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Term
| G Protein Coupled receptor |
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Definition
–Binding of the first messenger to the receptor leads to production of the second messenger
–Involves G proteins
•Gs: Activates amplifier enzyme
–Stimulatory G protein
•Gi: Inhibits amplifier enzyme
–Inhibitory G protein
–Purpose is signal amplifica |
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Term
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Definition
link ECF messenger to
–Ion channels
–Amplifier enzymes
GTP binding proteins
–Three subunits
abg
a subunit binds GTP and has GTPase activity |
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Term
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Definition
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Term
| Slow ligand-gated receptors |
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Definition
•Receptor and channel—different proteins
•Receptor and channel are linked by the G protein
•Binding of the ligand activates the G protein, which activates the channel
•Action is indirect |
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Term
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Definition
•Intracellular messengers
•Triggered by the first messenger (ligand) activating the G protein–coupled receptor
•The receptor activates the G protein
•The G protein activates the amplifier enzyme
•The amplifier enzyme activates second messenger production |
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Term
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Definition
Epinephrine
–Binds b-adrenergic receptor
–Receptor can interacts with G protein |
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Term
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Definition
Gs releases GDP and Binds GTP
• aGTP dissociates from bg subunits
• aGTP binds to Adenylate Cylclase |
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Term
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Definition
–Enzyme
–Catalyzes conversion of ATP to cAMP
–cAMP binds to and activates Protein Kinase A |
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Term
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Definition
second messanger
Active process to prevoc a response in the cell |
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Term
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Definition
–Activates Gq
– aq releases GDP and binds GTP
– a-GTP binds Phospholipase C |
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Term
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Definition
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Term
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Definition
catalyzes the conversion of Phosphotyidylinositol bisphosphate (PIP2) to 2 second messengers.
–Inositol trisphosphate (IP3)
–Diacylglycerol |
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Term
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Definition
Inositol trisphosphate (IP3)
–Diffuses through cytoplasm
–Binds IP3 Dependent Ca++ Channel in endoplasmic reticulum
–Ca++ is released from ER |
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Term
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Definition
–Stays associated with membrane
–Activates Protein Kinase C (PKC)
–PKC phosphorylates cellular targets |
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Term
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Definition
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Term
| IP3-dependent Ca++ Channel |
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Definition
–Diffuses through cytoplasm
–Binds IP3 Dependent Ca++ Channel in endoplasmic reticulum
–Ca++ is released from ER |
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Term
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Definition
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Term
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Definition
| Calmodulin stimulates this |
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Term
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Definition
•Small amounts of ligand can cause a huge response in the target
•Each step recruits more participants
•Characteristic of second messengers |
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Term
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Definition
| 1 signal can turn to 12 and 12 can turn to 500 and 500 can turn into 2,500,000 |
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