A&B Adrenoceptors Flashcards
(24 cards)
What is activated by α1-adrenoceptors?
Phospholipase C
This activation leads to increased IP3 and subsequent release of calcium
What are the effects of α1-adrenoceptor activation?
Contraction of smooth muscles, exocrine gland secretion, neuronal excitation
These effects are critical in various physiological responses
Fill in the blank:
Activation of α1-adrenoceptors leads to _______.
Phospholipase C activation
True or False: Activation of α1-adrenoceptors results in relaxation of smooth muscles.
False
What is the effect of activation of a2-adrenoreceptors?
Inhibition of adenylyl cyclase and decreased cAMP
This leads to various physiological effects including decreased norepinephrine release.
List some effects of a2-adrenoreceptor activation.
- Inhibition of norepinephrine release
- Decrease in secretion of aqueous humor
- Decrease in secretion of insulin
- Platelet aggregation
- Central nervous system effects
These effects illustrate the diverse roles of a2-adrenoreceptors in the body.
What does activation of B1-Adrenoceptors cause?
Adenylyl cyclase activation, increased cAMP, protein kinase activation
This leads to various physiological effects including increased heart functions.
List the effects of B1-Adrenoceptor activation.
- Increase in secretion of renin
- Increase in heart rate
- Increase in contractility
- Increase in conduction
What is the effect of activating B2-adrenoceptors?
Activation of B2-adrenoceptors causes Adenylyl cyclase activation, increased cAMP, and protein kinase activation
This process leads to various physiological responses.
What are the physiological responses caused by B2-adrenoceptor activation?
- Glycogenolysis
- Relaxation of smooth muscles
- Uptake of potassium in skeletal muscles
These responses are part of the body’s reaction to stress or exercise.
What does the activation of B3-adrenoceptors lead to?
Adenylyl cyclase activation, increased cAMP, protein kinase activation
This process is crucial for the stimulation of lipolysis.
What is the end result of B3-adrenoceptor activation?
Lipolysis
Lipolysis is the breakdown of fats and other lipids by hydrolysis.
What does activation of D1-receptors cause?
D- Dopamine receptor
D1, D2 Dopamine receptor subtype
Increased cAMP
cAMP stands for cyclic adenosine monophosphate, a second messenger important in many biological processes.
What effect does increased cAMP have on vascular smooth muscles?
D1 increases cAMP
Relaxation of vascular smooth muscles
This relaxation can lead to vasodilation, which is the widening of blood vessels.
What is the effect of D2-receptor activation on cAMP levels?
Decreased cAMP
cAMP is a secondary messenger important in many biological processes.
What happens to potassium currents when D2-receptors are activated?
Increased potassium currents
This change can influence neuronal excitability.
What is the effect of D2-receptor activation on calcium influx?
Decreased calcium influx
Calcium influx is critical for neurotransmitter release.
What systems are affected by the modulation of neurotransmission through D2-receptors?
Sympathetic and central nervous systems
These systems are crucial for the body’s response to stress and regulation of bodily functions.
What activates imidazoline receptors?
Adrenoceptor agonists and other substances that contain an imidazoline structure.
Which substance is one of the best-studied examples of imidazoline receptor activators?
Clonidine.
Where are imidazoline receptors found?
In the central nervous system and a number of peripheral tissues.
What is the primary effect of clonidine on blood pressure?
Antihypertensive effect.
How does clonidine exert its antihypertensive effect?
By activating both α2-adrenoceptors and imidazoline receptors in the central nervous system.
What is the result of activating imidazoline receptors and α2-adrenoceptors?
Reduced sympathetic outflow to the heart and vascular smooth muscle.
