33: Drug Action on Adrenergic Neurotransmitters Flashcards
Draw the structure of norepinephrine.
Draw the structure of epinephrine
Where is norepinephrine produced? What is it used for?
Produced in the **locus coeruleus **in the back of the pons and distibuted in various areas in the brain.
* released in response to stress
Explain the function of adrenergic neurotransmitters in the sympathetic nervous system.
Sympathetic activation of the adrenal glands –> adrenal medulla releases norepinephrine and epinephrine into the bloodstream –> functions as a hormone to further access to a wide variety of tissues.
What is the function of adrenergic neurotransmitters in the eyes?
An increase in production of tears –> making the eyes more moist and pupil dilation.
What is the function of adrenergic neurotransmitters in the lungs?
An increase in bronchodilation.
What is the function of adrenergic neurotransmitters in the heart?
An increase in the amount of blood pumped.
What is the function of adrenergic neurotransmitters in the arteries?
Constriction of blood vessels –> causing an increase in blood pressure
What is the function of adrenergic neurotransmitters in the stomach and intestines?
A reduction in digestive activity due to decreases in gastrointestinl mobility, blood flow, and secretion of digestive substances.
What is the function of adrenergic neurotransmitters in the stomach and intestines?
A reduction in digestive activity due to decreases in gastrointestinl mobility, blood flow, and secretion of digestive substances.
What is the function of adrenergic neurotransmitters in the liver?
An increase in production of glucose.
What is the function of adrenergic neurotransmitters in the kidneys?
Release of renin and retention of sodium in the bloodstream.
What is the function of adrenergic neurotransmitters in the pancreas?
Increased release of glucagon
* glucagon - a hormone that increases the production of glucose by the liver
What is the function of adrenergic neurotransmitters in the adipose tissue?
An increase in lipolysis
* lipolysis - conversion of fat to substances that can be used directly as energy sources by muscles and other tissues
What is the function of adrenergic neurotransmitters on the bladder?
Increase in contraction
What is the function of adrenergic neurotransmitters on the uterus?
Increase of activity
Explain the negative outcomes of reduced norepinephrine hormone levels.
- depression
- poor memory
- lack of energy
- lack of concentration
- lack of motivation
Explain the consequences of increased norepinephrine hormone levels.
- increased blood pressure
- increased heart rate
- hyperactive
- anxiety and stress
- irritability and insomnia
Describe the human diseases associated with high levels of norepinephrine and epinephrine.
Sympathetic hyperactivation: a distinctive set of symptoms including…
* aches and pains
* rapid heartbeat
* elevated blood pressure
* sweating
* palpitations
* anxiety
Stress: increases when increase of norepinephrine activity, which mobilizes the brain and body to meet the threat
Tumor of the adrenal medulla
Describe the human diseases associated with high levels of norepinephrine and epinephrine.
Sympathetic hyperactivation: a distinctive set of symptoms including…
* aches and pains
* rapid heartbeat
* elevated blood pressure
* sweating
* palpitations
* anxiety
Stress: increases when increase of norepinephrine activity, which mobilizes the brain and body to meet the threat
Tumor of the adrenal medulla
Explain where biosynthesis of adrenergic neurotransmitters begins.
Starts from tyrosine
* tyrosine is a natural amino acid in proteins
Explain aderenergic neurotransmitter biosynthesis: step 1.
Tyrosine is taken into the presynaptic neuron by Na+-dependent tyrosine transporter.
Explain aderenergic neurotransmitter biosynthesis: step 2.
Tyrosine is hydroxylated into DOPA by tyrosine hydroxylase (TH)
* a rate-limiting step
Explain aderenergic neurotransmitter biosynthesis: step 4 (storage).
Dopamine is taken into presynaptic vesicles by a H+-coupled vesicular monoamine transporter (VMAT).
Explain aderenergic neurotransmitter biosynthesis: step 6.
Norepinephrine is methylated into epinephrine by PNMT.
Explain aderenergic neurotransmitter biosynthesis: step 7 (release).
Vesicles move to the presynaptic terminal, which enforces Ca2+ channel to open and uptake of Ca2+ into the neuron.
Explain aderenergic neurotransmitter biosynthesis: step 8 (release)
Ca2+ ions activate the vesicles to fuse with the presynaptic membrane and release norepinephrine into the synaptic cleft.
* fusion process and release of norepinephrine can be inhibited by bretylium and guanethidine.
Explain aderenergic neurotransmitter biosynthesis: step 9 (removal)
A part of norepinephrine is diffused out of the synaptic cleft.
Explain aderenergic neurotransmitter biosynthesis: step 10 (reuptake)
A part of norepinephrine is retaken by NaCl-dependent norepinephrine transporter (NET)
* NET can be inhibited by cocaine and tricyclic antidepressants (TCAs)
Explain aderenergic neurotransmitter biosynthesis: step 11 (degradation)
A part of norepinephrine is metabolized into nometanephrine by COMT –> form inactive metabolite secreted into urine.
Explain aderenergic neurotransmitter biosynthesis: step 11 (degradation)
A part of norepinephrine is metabolized into nometanephrine by COMT –> form inactive metabolite secreted into urine.
Explain aderenergic neurotransmitter biosynthesis: step 12 (degradation)
A part of reuptake norepinephrine is metabolized into DOPGAL by MAO –> form inactive metabolite secreted into urine.
Explain the negative feedback mechanism of norepinephrine release.
A part of norepinephrine binds to the presynaptic neuron on the neuron membrane surface –> inhibits neurotransmitter release from the vesicles by a negative feedback mechanism.
