Sympathomimetics Flashcards
(116 cards)
1
Q
The major neurotransmitter of the sympathetic nervous system is?
A
Nor-adrenaline
2
Q
Neurons that are postganglionic sympathetic neurons with cell bodies in the sympathetic ganglia are called?
A
Noradrenergic neurons
3
Q
Examples of natural catecholamines include?
A
Epinephrine
Norepinephrine
Dopamine
4
Q
Examples of synthetic catecholamines include?
A
Isoprenaline
Dobutamine
5
Q
Non-catecholamines are also called β¦β¦., and examples include?
A
Sympathomimetic amines
Ephedrine, amphetamine, phenylephrine, Methoxamine and Mephebtermine
6
Q
In biosynthesis of norepinephrine, tyrosine is converted to β¦.. by tyrosine hydroxylase?
A
Dihydroxyphenylalanine (Dopa)
7
Q
What is the rate limiting step of biosynthesis of norepinephrine?
A
Tyrosine to dopa by tyrosine hydroxylase
8
Q
Conversion of tyrosine to dihydroxyphenylalanine by tyrosine hydroxylase requires ?
A
Tetrahydrobiopterin
9
Q
Conversion of tyrosine to dihydroxyphenylalanine by tyrosine hydroxylase is inhibited by?
A
Alpha-methyl tyrosine
10
Q
On biosynthesis is norepinephrine, Dopa is decarboxylated to dopamine by ?
A
L-aromatic amino acid decarboxylase (dopa decarboxylase)
11
Q
Decarboxylation of Dopa to dopamine requires β¦. As coenzyme?
A
Pyridoxine phosphate (vit B6)
12
Q
An enzyme used with levodopa in Parkinsonism treatment inhibits pyridoxin phosphate. What is it?
A
Carbidopa
13
Q
Dopamine is transported into vesicles then converted to norepinephrine by ?
A
Dopamine beta hydroxylase
14
Q
Conversion of dopamine to norepinephrine requires β¦. and is inhibited by β¦β¦. ?
A
Ascorbic acid (vitamin c)
Diethyldithiocarbamate
15
Q
Norepinephrine is converted to epinephrine by ?
A
Phenythanolamine N-methyl transferase (PNMT)
16
Q
The activity of phenythanolamine N-methyl transferase is stimulated by ?
A
Corticosteroids
17
Q
State a function of reserpine in norepinephrine biosynthesis?
A
It blocks transport into vesicles
18
Q
What are osmophilic granules and where are they found?
A
Aka synaptic vesicles, that are capable of storing high concentration of catecholamines (a complex of ATP & protein)
They are found in sympathetic nerve terminals, brain, adrenal medulla & sympathetic postganglionic terminals.
19
Q
Which uptake mechanism of norepinephrine requires energy for transport and is sodium and temperature dependent?
A
Uptake 1 and 2
20
Q
Uptake mechanism 1 is inhibited by?
A
Cocaine, ouabain, imipramine, amohetamines
21
Q
Uptake mechanism is located ?
A
In the presynaptic membrane (neuronal membrane)
22
Q
Uptake mechanism 2 is inhibited by?
A
Steroids
Phenoxybenzamine
23
Q
Metabolism of catecholamines is by ?
A
Monoamine oxidase
24
Q
A mitochondrial enzyme that oxidatively deaminates catecholamines, tyramine, serotonin and histamine is ?
A
MAO
25
MAO-A metabolizes β¦β¦ and is inhibited by ?
Norepinephrine
Tranylcypromine
26
MAO-B metabolizes β¦β¦. and is inhibited by ?
Dopamine
L-deprenyl catechol-o-methyl-transferase (COMT)
27
A soluble enzyme mainly found in the kidney and also post neuronal terminals and liver/intestine is ?
Dopamine
L-deprenyl catechol-o-methyl-transferase (COMT)
28
A class of G-protein coupled receptors that are target of catecholamines are ?
Adrenergic receptors
29
After binding of adrenergic receptors to its endogenous ligands, there is increase or decrease of 2nd messengers like ?
cAMP
IP3/DAG
30
After binding of adrenergic receptors to its endogenous ligands, there is increase or decrease of 2nd messengers and in some cases the G-protein itself operates ?
Potassium or calcium ion channels or increase prostaglandin production
31
Noradrenaline
Ephedrine
Dopamine
Phenylephrine
Methoxamine
Mephentermine are examples of ?
Pressor agents
32
Isoprenaline
Salbutamol
Terbutaline
Salmeterol
Formoterol
Bambuterol are examples of ?
Bronchodilators
33
Amphetamine
Dexamphetamine
Methamphetamine
Methylphenidate are examples of ?
CNS stimulants
34
Ritodrine
Isoxsuprine
Salbutamol
Terbutaline are examples of ?
Uterine relaxants
35
Adrenaline
Isoprenaline
Dobutamine are examples of ?
Cardiac stimulants
36
Xylometazoline
Oxymetazoline
Naphazoline
Phenylephrine
Phenylpropanolamine
Pseudoephedrine are examples of ?
Nasal decongestants
37
Amphetamine
Fenfluramine
Dexfenfluramine
Sibutramine are examples of
Anoretics
38
Example of non selective alpha adrenergic agonists include?
Norepinephrine
39
Examples of alpha 1 selective adrenergic agonists are ?
Phenylephrine
Ephedrine
Methoxamine
Metaraminol
Mephentamine
40
Examples of selective alpha 2 adrenergic agonists are ?
Clonidine
Alpha methyl dopa
Guanfacine
Guanabenz
41
Examples of non selective beta adrenergic agonists?
Epinephrine
Isoproterenol
42
Examples of selective beta 1 adrenergic agonists are?
Dobutamine
43
Examples of selective beta 2 adrenergic agonists are ?
Albuterol
Salbutamol
Terbutaline
Salmeterol
Reproterol
Oxiprenaline
Fenoterol
Isoxsuprine
Rimiterol
Ritodrine
Bitolterol
Isoetharine
44
Examples of indirect adrenergic agonists are?
Amphetamine
45
Alpha adrenergic receptor antagonist include?
Phenoxybenzamine
46
Agonist affinity for alpha adrenergic receptor is in what order?
Adrenaline > noradrenaline > Isoprenaline
47
Agonist affinity for beta adrenergic receptor is in what order?
Isoprenaline > adrenaline > noradrenaline
48
The difference between agonist affinity of alpha and beta adrenergic receptor is ?
Potassium ion channel opening and calcium channel opening respectively
49
Order of agonist affinity for both alpha and beta adrenergic receptor is?
Nor-adrenaline > adrenaline
50
Type 1 beta adrenergic receptors are found where?
Heart tissue
51
Receptors present in heart tissue and cause increased heart rate by acting on cardiac pacemaker cells are
Type 1 beta receptors
52
Where are type 2 beta adrenergic receptors found?
Vessels of skeletal muscle
Bronchial smooth muscle
53
What is the function of type 2 beta adrenergic receptors?
Cause vasodilation in skeletal muscle, which allows more blood to flow to the muscles and reduce total peripheral resistance
Cause Bronchodilation in bronchial smooth muscle
54
Type 3 beta adrenergic receptors are found where and function in?
Adipose tissue
Regulation of lipid metabolism
55
Why are beta 2 adrenergic agonists very useful in Rx of asthma?
Because beta receptors are responsible for bronchodilation & vasodepression
56
Stimulation of which receptors is associated with constriction of small blood vessels in the bronchial mucosa and relaxation of smooth muscles?
Alpha adrenergic receptors
57
Blood vessels of the skin and the genitourinary system possess what kind of adrenergic receptor?
Alpha 1 adrenergic receptor
58
Alpha 2 adrenergic receptors are found on?
Pre-synaptic nerve terminals
59
Alpha 1 adrenergic receptors act by?
Phospholipase C activation, which forms inositol triphosphate (IP3) and diacylglycerol (DAG)
60
Alpha 2 adrenergic receptors act by?
Inactivation of adenylate cyclase, cyclic AMP levels within the cell decrease
61
Increased systolic BP
Increased cardiac output
Decreased peripheral resistance
Decreased diastolic BP
Unchanged mean pressure are all effects of?
Norepinephrine in small doses
62
Decreased blood flow to skin and mucus membranes and renal beds is due to stimulation of?
Alpha effect (1 and 2) stimulation
63
Increased blood flow to skeletal muscles, coronary and liver vessels is due to stimulation of?
Beta 2 effect
64
What is the edge of Norepinephrine on blood pressure?
Causes rise in systolic, diastolic and mean blood pressure
65
Effect of Isoprenaline on blood pressure?
Causes rise in systoli blood pressure but fall in diastolic blood pressure, fall in mean blood pressure due to beta 1 and 2 action
66
On slow injection of norepinephrine, what happens to blood pressure?
It causes rise in systolic BP, but fall in diastolic BP, mean BP generally rises
67
Between alpha and beta receptors, which is more sensitive to adrenaline?
Beta receptors are more sensitive than alpha
68
Rapid IV injection of adrenaline is marked by?
1. Marked rise in systolic and diastolic BP
2. Large concentration of alpha action predominates
3. Vasoconstriction in skeletal muscle
4. BP returns to normal
69
A secondary fall in mean BP which occurs as a result of rapid uptake and dissipation of adrenaline at low concentrations marked by loss of alpha action but beta action predominates is called?
Daleβs vasomotor reversal phenomenon
70
Explain Daleβs vasomotor reversal phenomenon?
A secondary fall in mean BP which occurs as a result of rapid uptake and dissipation of adrenaline at low concentrations marked by loss of alpha action but beta action predominates is called?
71
Action of adrenaline on respiratory system?
Powerful bronchodilator, relaxes bronchial smooth muscle
72
Adrenaline mediates its effect through which receptors in the respiratory system ?
Beta 2
73
Action of adrenaline on GIT causes?
1. Relaxation of gut muscles and constricted sphincters
2. Reduced peristalsis
74
Adrenaline mediated its effects on the GIT through which receptors?
Aloha and beta receptors
75
Action of adrenaline on bladder are?
1. Relaxed detrusor muscle
2. Trigone constriction
3. Both are anti voiding
76
Action of adrenaline on uterus includes?
1. Contracts (when not pregnant) and relaxes uterus (when pregnant)
77
Adrenaline action on bladder is mediated by which receptor?
Beta
78
Adrenaline action on uterus is mediated by which receptor?
Alpha and beta
79
Action of adrenaline on skeletal muscle include?
Abbreviated active state and less tension in slow conducting fibres and enhanced muscle spindle firing called tremor
80
Alpha and beta mediation of adrenaline action on skeletal muscle is by?
Facilitation of Ach release in NMJ (alpha 1) and directly on muscle fibers (beta 2)
81
Adrenaline effects on CNS?
No visible clinical effects in normal doses because of low penetration except restlessness, apprehension and tremors
82
Activation of alpha 2 in CNS decreasing sympathetic outflow and reduction in blood pressure and bradycardia is the action of which drug?
Clonidine
83
Effect of adrenaline on glucose and lactic acid?
Increases there concentration
84
Adrenaline stimulation of calorigenesis is mediated by which receptors?
Beta 2 and beta 3
85
Adrenaline effect on insulin?
Inhibits secretion via alpha 2
86
Effect of adrenaline on uptake of glucose by peripheral tissue?
Decrease
87
Effect of adrenaline on glycogenolysis?
Stimulates it via beta receptor
88
Effect of adrenaline on free fatty acids
Increases FFA concentration in blood
89
Effect of adrenaline on potassium?
Hypokaleamia with initial hyperkalemia
90
How effective are catecholamines orally?
All Catecholamines are ineffective orally.
91
The primary drugs used as IV vasopressors in the hospital are
dopamine and norepinephrine.
92
Dobutamine is given IV as an β¦β¦...
inotrope
93
Dobutamine is given β¦.. as an inotrope.
IV
94
Albuterol is used via β¦β¦.. or β¦β¦β¦ for asthma.
nebulizer
metered-dose inhaler
95
Adrenaline is absorbed slowly from β¦β¦β¦ and faster from β¦β¦β¦β¦.
Absorbed slowly from subcutaneous tissue
Faster from IM site
96
How effective is adrenaline locally administered by inhalation?
Inhalation is locally effective
97
Adrenaline is not usually given by β¦β¦
IV
98
Adrenaline is rapidly inactivated in β¦β¦β¦ by β¦β¦β¦ and β¦β¦.?
Liver
MAO
COMT
99
Sympathomimetic drugs are used to β¦β¦β¦β¦β¦.. of the sympathetic nervous system for therapeutic benefit.
augment endogenous catecholamines
100
What is the mechanism of action of Phenylephrine?
activation of Ξ±-1 adrenoceptors β β total peripheral resistance:
101
Does Phenylephrine stimulate cardiac adrenoceptors?
Does not stimulate cardiac adrenoceptors
102
Phenylephrine increase TPR which induces β¦β¦β¦.. (a counter-regulatory mechanism)
reflex bradycardia
103
Phenylephrine Contracts smooth muscle in the β¦β¦β¦.
splanchnic vessels
104
About Phenylephrine, Actions quantitatively similar to noradrenaline.
Actions qualitatively similar to noradrenaline.
105
Phenylephrine is Resistant to MAO and COMT, true or false?
True
106
Does Phenylephrine cross the BBB?
Does not cross BBB, so no CNS effects
107
Therapeutic Effects of Phenylephrine on the eye and nose?
Produces mydriasis and nasal decongestion
108
Therapeutic Effects of Phenylephrine on the eye and nose?
Produces mydriasis and nasal decongestion
108
How is Phenylephrine administered?
Administered parenteraly & topically (eye, nose
109
About indications for Phenylephrine use. Hypovolaemic shock as β¦β¦..?
pressor agent to increase BP in shock states
110
About indications for Phenylephrine use. As hypertensive agent during β¦β¦β¦.?
spinal anaesthesia
111
About indications for Phenylephrine use. Used topically as a β¦β¦β¦β¦. to relieve β¦β¦β¦.. due to allergic rhinitis & Sinusitis
vasoconstrictor
nasal congestion
112
About indications for Phenylephrine use. Used in topical ophthalmic preparations to promote β¦β¦β¦ and β¦β¦β¦
mydriasis
conjunctival blood vessel
constriction
113
About indications for Phenylephrine use. An additive to topical hemorrhoid preparations to promote β¦β¦β¦.?
hemorrhoidal venous vasoconstriction
114
About indications for Phenylephrine use. Mydriatic in the form of eye drops and lowers β¦β¦..?
intraocular pressure
115
Adverse drug reactions of Phenylephrine include?
Photosensitivity, conjunctival hyperemia and hypersensitivity
