L3 - G-Protein Coupled Receptors 2 Flashcards
What is the fight or flight response?
The fight or flight response is a physiological reaction to a perceived threat, which prepares the body to either fight or flee from danger. It was originally developed to protect us from predators but is now often triggered by acute stress such as before an important exam or presentation.
What are the key components involved in the fight or flight response?
The fight or flight response involves the brain, sympathetic nervous system (SNS), and the adrenal medulla. These components work together to activate various physiological changes that prepare the body for action.
How does adrenaline increase oxygen uptake during the fight or flight response?
Adrenaline increases oxygen uptake by:
Increasing airway diameter: This allows for easier airflow into the lungs, enhancing oxygen intake.
Increasing respiratory rate: This helps to increase the amount of oxygen brought into the body with each breath.
Why is oxygen delivery important in the fight or flight response?
Oxygen delivery is crucial as it provides the energy needed by key organs, such as the brain, skeletal muscle, cardiac muscle, and liver, to function optimally during stressful or dangerous situations.
How does adrenaline increase glucose delivery during the fight or flight response?
Adrenaline increases glucose delivery by:
Increasing glucose release into the bloodstream: This provides energy for the body’s vital organs and muscles.
Decreasing glucose uptake from the bloodstream into adipose tissue: This ensures more glucose is available for immediate use by muscles and the brain.
How does adrenaline increase the delivery of oxygen and glucose to key organs?
Adrenaline increases the delivery of oxygen and glucose by:
Increasing heart rate: This ensures faster blood circulation to deliver oxygen and glucose more quickly to vital organs and muscles.
Increasing contractile force: This boosts the heart’s pumping ability, enhancing blood flow to organs like the brain, skeletal and cardiac muscles, and the liver.
How does adrenaline direct the flow of oxygen and glucose to key organs?
Adrenaline directs the flow by:
Increasing the diameter of blood vessels supplying key organs: This allows for more oxygen and glucose to be delivered to vital organs like the brain, skeletal & cardiac muscles, and the liver.
Decreasing the diameter of blood vessels supplying non-essential organs: This diverts blood away from less critical organs (like the digestive system) to prioritize key organs during a stress response.
What happens when adrenaline binds to β1/2-adrenoceptors?
Adrenaline binding activates the Gs protein.
What does the activated Gs protein do?
The activated Gs protein stimulates adenylate cyclase.
What does adenylate cyclase do?
Adenylate cyclase converts ATP to cAMP (cyclic AMP).
What is the role of cAMP?
cAMP activates Protein kinase A (PKA).
What does Protein kinase A (PKA) do?
PKA phosphorylates target proteins, leading to cellular changes like increased heart rate (β1) or bronchodilation (β2).
What type of receptor does adrenaline act on in the fight or flight response?
Adrenaline acts on the α-1 adrenoceptor.
What G-protein is associated with the α-1 adrenoceptor?
The α-1 adrenoceptor is coupled with the Gq protein.
What enzyme does Gq activate in the α-1 adrenoceptor signaling pathway?
Gq activates phospholipase C (PLC).
What molecule is generated by phospholipase C (PLC) activation?
PLC generates inositol trisphosphate (IP3) and diacylglycerol (DAG).
What is the effect of IP3 on intracellular calcium?
IP3 stimulates the release of Ca²⁺ from the endoplasmic reticulum (ER).
How does DAG contribute to the signaling pathway?
DAG activates protein kinase C (PKC), leading to various cellular responses.
What is the overall result of the α-1 adrenoceptor activation in the fight or flight response?
The activation of the α-1 adrenoceptor triggers a series of intracellular events, leading to the release of calcium from the ER and the activation of PKC, contributing to the fight or flight response.
What type of molecule is GTP in the context of the α-1 adrenoceptor signaling pathway?
GTP is a molecular switch that activates the Gq protein
What does the acronym “PIP2” refer to in the signaling cascade?
PIP2 (phosphatidylinositol 4,5-bisphosphate) is the substrate cleaved by PLC to generate IP3 and DAG.
What receptor does IP3 bind to in the signaling cascade?
IP3 binds to the IP3 receptor (IP3 R) on the endoplasmic reticulum to release Ca²⁺.
How does adrenaline increase the delivery of oxygen and glucose to key organs?
Adrenaline increases oxygen and glucose delivery by enhancing the function of key organs such as the brain, skeletal and cardiac muscles, and the liver.
How does adrenaline increase oxygen uptake?
Adrenaline increases oxygen uptake by increasing airway diameter and respiratory rate.
What is the effect of increased airway diameter in the presence of adrenaline?
Increased airway diameter allows for greater airflow, improving oxygen intake and the removal of carbon dioxide.
What role does the increased respiratory rate play in oxygen uptake?
Increased respiratory rate enhances oxygen intake and accelerates the removal of carbon dioxide.
How does adrenaline affect myosin light chain (MLC) in muscle contraction?
Adrenaline activates the β2-adrenoceptor, leading to the activation of Gs, which increases cAMP levels and activates protein kinase A (PKA). PKA then phosphorylates and inactivates myosin light chain kinase (MLCK), preventing muscle contraction.
What is the role of myosin light chain kinase (MLCK) in smooth muscle contraction?
MLCK normally phosphorylates myosin light chain (MLC), which leads to smooth muscle contraction.
How does adrenaline lead to smooth muscle relaxation?
Adrenaline binds to the β2-adrenoceptor, activates Gs, increases cAMP levels, activates PKA, which inactivates MLCK, preventing the phosphorylation of MLC, leading to smooth muscle relaxation.
What is the outcome of smooth muscle relaxation in the bronchioles?
Relaxation of smooth muscle in the bronchioles results in their dilation, improving airflow and gas exchange, contributing to increased oxygen uptake and carbon dioxide removal.
What is the effect of increased cAMP levels in the presence of adrenaline?
Increased cAMP levels activate PKA, which phosphorylates MLCK, inhibiting its action and causing smooth muscle relaxation.
What is the overall effect of adrenaline on bronchiole smooth muscle?
Adrenaline leads to bronchiole smooth muscle relaxation through the β2-adrenoceptor, resulting in bronchodilation and improved gas exchange, contributing to enhanced oxygen uptake and carbon dioxide removal.
How does adrenaline increase the delivery of glucose to key organs?
Adrenaline increases glucose delivery by increasing glucose release into the bloodstream and decreasing glucose uptake into adipose tissue.
How does adrenaline increase glucose levels in the blood?
Adrenaline increases glucose levels by stimulating the release of glucose from the liver into the bloodstream.
What effect does adrenaline have on glucose uptake in adipose tissue?
Adrenaline decreases the uptake of glucose from the bloodstream into adipose tissue.
How does the increase in glucose in the bloodstream benefit key organs during the fight or flight response?
The increased glucose in the bloodstream provides key organs, such as the brain, skeletal and cardiac muscles, and the liver, with the necessary energy to respond to stress or danger.
What are the two key processes involved in elevating blood glucose levels during the metabolic changes induced by adrenaline?
The two key processes are increased lipid breakdown (lipolysis) in adipose tissue and increased glucose release from the liver.
How does adrenaline affect adipose tissue during the metabolic response?
Adrenaline increases lipid breakdown (lipolysis) in adipose tissue and decreases glucose uptake from the bloodstream.
How does the liver contribute to increasing blood glucose levels?
The liver increases blood glucose levels by increasing glycogen breakdown and enhancing gluconeogenesis.
What is the result of increased glycogen breakdown in the liver?
Increased glycogen breakdown in the liver results in the release of glucose into the bloodstream.
What role does gluconeogenesis play in increasing blood glucose levels?
Gluconeogenesis in the liver generates new glucose molecules, which are released into the bloodstream, further elevating blood glucose levels.
What is the overall effect of these metabolic changes during the fight or flight response?
The metabolic changes increase blood glucose levels, providing essential energy to key organs, including the brain, skeletal and cardiac muscles, and the liver.
How does adrenaline affect cardiac rate and contractility?
Adrenaline activates β1-adrenergic receptors (β1-AR) in the heart, leading to increased cardiac rate (chronotropic effect) and contractile force (ionotropic effect).
What is the role of PKA in myocardial contraction?
PKA phosphorylates calcium channels, increasing their opening and leading to higher intracellular calcium levels.
How does increased calcium contribute to myocardial contraction?
Increased calcium levels enhance both the cardiac rate (chronotropic effect) and the force of contraction (ionotropic effect), resulting in greater cardiac output.
What is the overall effect of adrenaline on cardiac output?
Adrenaline increases cardiac output by enhancing cardiac rate and contractility, improving the delivery of oxygen and glucose to key organs such as the brain, skeletal and cardiac muscles, and the liver.
How does the β1-adrenergic receptor signaling pathway increase calcium in cardiac tissue?
β1-AR activation stimulates adenylate cyclase (AC), increasing cAMP levels, which activate PKA. PKA then phosphorylates calcium channels, resulting in increased intracellular calcium concentration.
What is the effect of increased calcium levels in the heart?
Increased calcium levels lead to stronger heart contractions (ionotropic effect) and faster heart rate (chronotropic effect), boosting cardiac output.
How does adrenaline direct the flow of oxygen and glucose to key organs?
Adrenaline directs the flow of oxygen and glucose by enhancing blood flow to key organs such as the brain, skeletal and cardiac muscles, and the liver while redirecting blood away from less critical areas.
What effect does adrenaline have on the smooth muscles of blood vessels?
Adrenaline causes smooth muscle relaxation in blood vessels supplying critical organs, leading to vasodilation, and contraction in non-essential areas, leading to vasoconstriction.
How does adrenaline influence glucose availability to key organs?
Adrenaline increases glucose availability by stimulating glycogen breakdown in the liver and decreasing glucose uptake in adipose tissue, ensuring glucose is available for critical organs.
What happens to blood flow in response to adrenaline during the fight or flight response?
Blood flow is increased to vital organs such as the brain, heart, and muscles, while blood flow is reduced to less critical areas, optimizing energy delivery during stress.
How does adrenaline affect blood flow to key organs?
Adrenaline increases blood flow to key organs by binding to β2-adrenoceptors on the smooth muscle of arterioles supplying these organs.
What happens when adrenaline binds to β2-adrenoceptors on smooth muscle?
Binding of adrenaline to β2-adrenoceptors activates adenylate cyclase, increasing cAMP levels, which activate PKA and lead to the phosphorylation and inactivation of myosin light chain kinase (MLCK), causing smooth muscle relaxation.
What is the effect of MLCK inactivation on blood flow?
Inactivation of MLCK prevents the phosphorylation of myosin light chain (MLC), leading to smooth muscle relaxation, which allows more blood to flow to key organs.
What is the role of PKA in regulating blood flow during the fight or flight response?
PKA phosphorylates MLCK, leading to its inactivation, which causes smooth muscle relaxation and increases blood flow to vital organs.
How does cAMP contribute to the regulation of blood flow?
cAMP, produced by adenylate cyclase in response to adrenaline binding to β2-adrenoceptors, activates PKA, which in turn causes the relaxation of smooth muscle and increases blood flow to key organs.
How does adrenaline affect peripheral blood vessels (BV)?
Adrenaline binds to α1-adrenoceptors, activating Gq and increasing IP3 levels, which leads to vasoconstriction in peripheral blood vessels.
What is the role of IP3 in smooth muscle contraction?
IP3 increases intracellular calcium levels by releasing calcium from the sarcoplasmic reticulum (SR).
What does released calcium bind to in smooth muscle contraction?
Released calcium binds to calmodulin (CaM), forming a Ca²⁺-CaM complex.
How does the Ca²⁺-CaM complex affect myosin light chain kinase (MLC-K)?
The Ca²⁺-CaM complex activates myosin light chain kinase (MLC-K), which phosphorylates myosin light chain (Myosin-LC), resulting in smooth muscle contraction.
What is the effect of smooth muscle contraction on blood flow?
Smooth muscle contraction leads to vasoconstriction, reducing blood flow to non-essential organs, such as the GI tract and kidneys.
What is the overall effect of adrenaline on blood flow to non-essential organs?
Adrenaline causes vasoconstriction in peripheral blood vessels, reducing blood flow to non-essential organs and prioritizing blood flow to key organs like the brain, heart, and muscles.
What is music performance anxiety (MPA)?
Music performance anxiety (MPA) is when musicians find it difficult to perform in front of others, particularly audiences.
How is MPA classified in terms of severity?
MPA is a continuum of severity, where performance may be improved, worsened, or even impossible due to anxiety, and symptoms vary from person to person.
How is MPA classified in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5)?
MPA is classified as a subtype of social anxiety disorder, specifically the performance-only subtype.
Can anxiety affect musical performance in different ways?
Yes, anxiety can either improve performance, hinder it, or make it impossible for the musician to play, depending on the severity and the individual.
What are the main physiological symptoms of music performance anxiety (MPA)?
The main physiological symptoms of MPA include tachycardia, sweating, tremor, blurred vision, and increased rate and depth of breathing.
How does tachycardia manifest in MPA?
Tachycardia in MPA is characterized by an abnormally fast heart rate, often due to anxiety during performance.
What role does sweating play in MPA?
Sweating is a common physiological response to anxiety, indicating the body’s stress reaction during performance.
How does tremor affect musicians with MPA?
Tremor refers to involuntary shaking or trembling, often occurring in the hands or body, making it difficult to play an instrument.
What causes blurred vision in MPA?
Blurred vision in MPA can occur as a result of heightened anxiety, leading to physical changes in vision and focus.
How does increased breathing rate and depth affect musicians with MPA?
Increased rate and depth of breathing occur as part of the body’s “fight or flight” response, which can lead to hyperventilation during anxiety-provoking situations like performing.
What are some common physical symptoms of music performance anxiety (MPA)?
Common physical symptoms of MPA include tremor, sweating, increased heart rate and contractility, shortness of breath, sweaty palms, and shaking hands.
How does MPA affect oxygen uptake and glucose delivery?
MPA triggers an increase in oxygen uptake and glucose delivery to muscles, as part of the body’s “fight or flight” response.
What effect do beta-blockers, such as propranolol, have on MPA symptoms?
Beta-blockers reduce peripheral sympathetic responses by blocking beta-adrenoceptors, which helps decrease physical symptoms like sweating, tremor, tachycardia, and rapid breathing, but they do not affect the emotional component of anxiety.
Why is propranolol used for MPA?
Propranolol is used to alleviate the physical symptoms of anxiety, such as tremors and tachycardia, but it does not address the emotional or affective aspects of anxiety.
How does beta-blocker use help musicians with MPA?
Beta-blockers reduce the physical symptoms like trembling hands and sweaty palms, making it easier for musicians, particularly violinists, to perform.
What is the effect of MPA on energy levels in muscles?
MPA increases energy in muscles by enhancing oxygen and glucose delivery, preparing the body for action, but this can also contribute to feelings of physical tension or discomfort during performance.
How does adrenaline increase the delivery of oxygen and glucose to key tissues?
Adrenaline increases oxygen and glucose delivery by enhancing blood flow to key tissues such as the brain, skeletal muscles, and the liver during the fight or flight response.
What are the key tissues that receive increased oxygen and glucose during the fight or flight response?
The key tissues include the brain, skeletal muscles, and the liver.
What physical symptoms can result from adrenaline’s action in the fight or flight response?
Physical symptoms include tremor and sweating, as part of the body’s heightened stress response.
What is the overall effect of adrenaline on the body during the fight or flight response?
Adrenaline boosts oxygen and nutrient delivery to critical organs, preparing the body for rapid action, but can also trigger physical symptoms like tremor and sweating.
