Autonomic Control of Metabolism Flashcards
What is the process of synthesising noradrenaline from tyrosine?
In the terminal button of a neuron tyrosine is converted into DOPA by tyrosine hydroxylase. DOPA is then converted into Dopamine by DOPA decarboxylase. The Dopamine travels through a vesicular monoamine transported into a vesicle where it is then converted into noradrenaline by Dopamine beta-hydroxylase
How does an action potential cause the release of neurotransmitters?
When the action potential reaches the axon terminal it causes calcium ion channels to open increasing the Ca+ concentration in the cell. This causes the vesicle to fuse with the cell membrane, causing the neurotransmitters to be released into the synapes
How is the action of noradrenaline terminated?
Reuptake into presynaptic neuron
Enzymatic breakdown
Where is adrenaline made?
Adrenal medulla
Which enzyme converts noradrenaline into adrenaline?
PNMT
True or False:
Alpha-receptors are only activated by noradrenaline
False
Both adrenaline and noradrenaline activates the alpha-receptor but noradrenaline activates it more
Which molecule activates a beta-receptor more, adrenaline or noradrenaline?
Adrenaline
Which cytoplasmic loop of the GPCR is the most important to function?
3rd
It couples to G-proteins
In which tissues are Beta1-receptors found?
Heart
Liver
Skeletal muscle
In which tissues are Beta2-receptors found?
Lungs
Blood vessel beds of skeletal muscle
In which tissues are Beta3-receptors found?
Adipose cells
What is the effect of beta-receptor activation in the liver?
Glycogenolysis (B1)
What is the effect of beta-receptor activation in the skeletal muscle?
Glycogenolysis (B1)
Glucose uptake (B2)
Thermogenesis (B3)
What is the effect of beta-receptor activation in white adipose tissue?
Lipolysis (B3)
What is the effect of beta-receptor activation in brown adipose tissue?
Thermogenesis (B3)
In the liver, which enzymes are activated/inhibited by adrenaline?
Activated: glycogen phosphorylase
Inhibited: glycogen synthase
In the muscle, which enzymes are activated/inhibited by adrenaline?
Activated: glycogen phosphorylase
Inhibited: glycogen synthase
In the fat, which enzymes are activated/inhibited by adrenaline?
Activated: lipase
True or False:
Adrenaline can stimulate glucose uptake into muscle independent of insulin
True
What is the adrenal cortex?
the outer portion of the adrenal gland located on top of each kidney. The adrenal cortex produces steroid hormones which regulate carbohydrate and fat metabolism and mineralocorticoid hormones which regulate salt and water balance in the body
What is the adrenal medulla?
the inner portion of adrenal gland. The adrenal medulla makes adrenaline and noradrenaline.
What is adrenaline?
a hormone that is secreted by the adrenal medulla in response to stress and increases heart rate, breathing rate and blood pressure, and raises the blood levels of glucose and lipids
What is an alpha-adrenoreceptor?
a class of GPCRs targeted by noradrenaline and adrenaline. Common effects of α-receptors include vasoconstriction of veins and a decrease in motility of smooth muscle in the GI tract
What is the autonomic nervous system?
the part of thenervous systemthat controls and regulates the internal organs without any conscious recognition or effort by the organism. Theautonomic nervous systemcomprises two antagonistic sets ofnerves, the sympathetic and parasympatheticnervous systems.
What is a barbituate?
a drug that acts as a central nervous system depressant, and can therefore produce a wide spectrum of effects, from mild sedation to total anesthesia
What is a Beta1-receptor?
a class of GPCRs targeted by noradrenaline and adrenaline. Common effects of the β1-receptor include an increase in cardiac output, glycogenolysis, renin secretion from the kidneys and ghrelin secretion from the stomach.
What is a Beta2-receptor?
a class of GPCRs targeted by noradrenaline and adrenaline. Common effects of the β2-receptor include smooth muscle relaxation, lipolysis, glycogenolysis and insulin secretion
What is a Beta3-receptor?
a class of GPCRs targeted by noradrenaline and adrenaline. Common effects of the β3-receptor include enhancement of lipolysis in white adipose tissue and thermogenesis in brown adipose tissue
What is brown adipose tissue (BAT)?
a type of adipose tissue with its primary function being thermoregulation. Brown adipocytes contain numerous small droplets of lipids and a mu higher number of mitochondria, which give it its brown appearance
What is clenbuterol?
a drug that acts as a β2 agonist which increases oxygen uptake and glycogenolysis. Clenbuterol is a common performance enhancing drug
What is cytochrome p450?
proteins of the superfamily containing heme as a cofactor. They are, in general, the terminal oxidase enzymes in electron transfer chains
What is diazepam?
a drug, also known as Valium, that is a part of the benzodiazepine family that produces a calming effect
What is dobutamine?
a drug that acts as a β1 agonist which increases cardiac output. This drug is commonly used to treat heart failure