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18 Cards in this Set
- Front
- Back
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What type of receptor is alpha-1? Where is the receptor located? |
It is a Gq/11 receptor and is located in the smooth muscle of blood vessels where it results in constriction, because it stimulates calcium release |
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What type of receptor is alpha-2? Where is the receptor located? |
It is a Gi receptor and is located on the presynaptic membrane of cells where it functions as an auto receptor. |
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Where are each of the beta receptors located? |
B1: Found in the heart, kidneys and presynaptic terminal B2: Bronchiolar, uterine and GI smooth muscle and dilate vessels to skeletal muscle B3: Lipolysis and smooth muscle relaxation |
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Where is epinephrine released from? |
It is released from the adrenal medulla |
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What receptors does epinephrine interact with? |
a1,2 and B1,2 |
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What receptor has the greatest affinity for epinephrine? |
B2 and therefore at low concentrations it preferentially binds this receptor which induces bronchiolar smooth muscle relaxation |
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Why is the effect of concentration more significant for epinephrine compared to other ANS transmitters? |
Because it is found in the plasma it distributes throughout the body |
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How does the vasoactivity response progress? |
At low concentrations epinephrine preferentially binds B2 and causes a vasodilatory response to the vessels supplying skeletal muscle As concentrations increase the alpha receptors have a stronger effect and result in vasoconstriction (because of increases to calcium levels) |
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What interaction results in bronchial smooth muscle relaxation? |
Binding to the B2 receptor causes relaxation of bronchial smooth muscle (fight or flight) |
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How does the SNS cause increases in blood glucose and free fatty acid? |
The B3 receptor is activated which results in lipolysis releases fats and glucose |
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What receptors does Norepinephrine interact with? |
It binds to a1,2 and B1 receptors |
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Why is the effect on the blood pressure potentiated by binding to both alpha and beta receptors? |
Because the B1 receptor causes increased HR and the a1 receptor causes an increase in vasoconstriction |
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What are the targets of norepinephrine? What is the effect of this? |
B1 and B2 receptors. This means that the drug primarily has effects on blood pressure by increasing heart rate but simultaneously vasodilating arteries supplying skeletal muscle |
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What is the target of clonidine and what does this produce, why? |
The target of clonidine is solely alpha-2 (agonist) meaning it binds the autoreceptor (primarily found on neurons effecting vasculature) therefore it prevents the release of NE and binding to alpha-1 which causes vasoconstriction. Because of this clonidine is used as an hypertensive |
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What are the concentration dependent effects of clonidine? |
At low concentrations clonidine preferentially binds the auto receptor and prevents vasoconstriction, but at high concentrations it binds receptors on the vascular smooth muscle causing vasoconstriction |
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What is the target of dobutamine? And what effect does it have? |
It binds to the B2 receptor and causes an increase in heart rate (for this reason it is used to treat heart failure) |
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What is the target of salbutamol? And what is its role? |
Salbutamol is a B2 agonist that is used to induce bronchodilation |
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What is the role of cocaine? |
Inhibits the NET which prevents reuptake of NE and therefore increases sympathetic activity |
