Sympathetic NS

Question 1

what neurones and receptors are involved in the sympathetic NS?

Answer 1

Ach on nicotinic receptors and NA on alpha/beta receptors

Question 2

how is adrenaline release stimulated?

Answer 2

a cell body releases Ach on nicotinic receptor in adrenal tissue which then causes stimulation of adrenaline release

Question 3

what are the two sources of outflow?

Answer 3

thoracic and lumbar

Question 4

what is Thoracic outflow?

Answer 4

the spine in the upper back and lower abdomen

Question 5

what is lumbar outflow?

Answer 5

the spine in the lower back

Question 6

where are the ganglia that are involved in sympathetic NS?

Answer 6

close to the spinal cord

Question 7

what is the pathway that results in NA onto alpha/beta receptors?

Answer 7

tyrosine - dopa - dopamine - NA in storage vesile - NA release

Question 8

where do the neurones that release NA exist in the body?

Answer 8

in the brain as well as the sympathetic NS

Question 9

what did dale provide evidence for?

Answer 9

that two distinct classes of adrenoreceptor exist

Question 10

how did dale discover this?

Answer 10

observed that a vasoconstrictor effect of adrenaline becomes a vasodilator effect when pre-treated with ergot

Question 11

what effect did ergot have in this observation?

Answer 11

in the absence of ergot, there was a large alpha mediated constriction yet when ergot blocked alpha, there was a large beta mediated dilation

Question 12

what did ahlquist do?

Answer 12

observed responses to adrenaline, NA and isoprenaline in smooth muscle

Question 13

what are alpha receptors sensitive to?

Answer 13

highly sensitive to adrenaline and noradrenaline

Question 14

what are alpha receptors not sensitive to?

Answer 14

isoprenaline

Question 15

what are beta receptors sensitive to?

Answer 15

highly sensitive to isoprenaline

Question 16

what are beta receptors less sensitive to?

Answer 16

more sensitive to adrenaline than noradrenaline

Question 17

what did lands do?

Answer 17

identified two types of beta receptor

Question 18

what does beta 1 receptor cause?

Answer 18

increases in rate and force of cardiac contraction

Question 19

what do beta 2 receptors do?

Answer 19

mediate bronchodilation and vasodilation

Question 20

what do alpha 1 receptors do?

Answer 20

vasoconstriction and contraction

Question 21

what do alpha 2 receptors do?

Answer 21

inhibition of NA release

Question 22

what do direct drugs do?

Answer 22

mimic or block the effect of NA/A by acting on beta or alpha receptors

Question 23

what do indirectly acting drugs do?

Answer 23

increase or decrease NA availability by non-receptor mechanisms

Question 24

what are examples of ways in which an increase or decrease in NA is caused?

Answer 24

block of neuronal uptake or inhibition of MAO

Question 25

what do directly acting alpha 1 agonists do?

Answer 25

mimic the effect of NA/A causing vasoconstriction in vascular smooth muscle

Question 26

what is an example of a directly acting alpha 1 agonist?

Answer 26

phenylephrine

Question 27

what are the clinical uses of alpha 1 agonists?

Answer 27

they cause vasoconstriction so nasal decongestion and raising low blood pressure

Question 28

what effect do alpha 1 antagonists have?

Answer 28

inhibit vasoconstriction so reduces blood pressure

Question 29

what is an example of an alpha 1 antagonist?

Answer 29

prazosin

Question 30

what are the clinical uses for alpha 1 antagonists?

Answer 30

relaxing prostatic smooth muscle to allow urine flow

Question 31

how is NA able to limit its own release?

Answer 31

as stimulation of alpha 2 adrenoceptors inhibits NA release

Question 32

what does a reduction in NA release cause?

Answer 32

reduction in vasoconstriction and lower BP

Question 33

what does NA cause?

Answer 33

contraction of smooth muscle

Question 34

what is an example of an alpha 2 agonist?

Answer 34

clonidine

Question 35

what do alpha 2 agonists do?

Answer 35

stimulate alpha 2 agonists which prevent NA release

Question 36

what do alpha 2 antagonists do?

Answer 36

block the inhibition of NA release by blocking the alpha 2 receptor

Question 37

what effect do alpha 2 antagonists have?

Answer 37

increase the amount of NA available to stimulate the postsynaptic receptors

Question 38

what is an example of an alpha 2 antagonist?

Answer 38

yohimibine idazoxane

Question 39

what type of drug is not used clinically?

Answer 39

alpha 2 antagonists

Question 40

what does beta adrenoceptor stimulation cause?

Answer 40

causes heart rate and force of contraction to increase and more renin released from the kidney which also causes an increased BP

Question 41

what are the clinical uses of beta agonists and antagonists?

Answer 41

cardiac arrest and low BP

Question 42

what is dobutamine?

Answer 42

beta 1 agonist

Question 43

what are beta 1 antagonists used to treat?

Answer 43

hypertension and angina

Question 44

what are the non-selective beta drugs?

Answer 44

propanolol and timolol

Question 45

what are the beta 1 selective drugs?

Answer 45

atenolol

Question 46

what do beta 2 agonists do?

Answer 46

cause stimulation of beta 2 receptors causing bronchodilation and vasodilation

Question 47

what are beta 2 agonists used to treat?

Answer 47

asthma

Question 48

what are some examples of beta 2 agonists?

Answer 48

salbutamol, fenoterol and salmeterol

Question 49

what are the adverse effects of beta 2 agonists?

Answer 49

tachycardia and fine muscle tremor if beta 2 stimulation

Question 50

are there any beta 2 antagonist clinical uses?

Answer 50

no, however used for pharmacological research

Question 51

what does MAO do?

Answer 51

converts NA that has been uptakes from the synaptic cleft into deaminated metabolites

Question 52

what do MAO inhibitors do?

Answer 52

increase the synaptic availability of NA by blocking its breakdown

Question 53

what is phenelzine?

Answer 53

an MAO blocker

Question 54

what effect does cocaine have?

Answer 54

it blocks the neuronal uptake of NA increasing its synaptic concentration

Question 55

what does cocaine block?

Answer 55

the dopamine transporter in dopaminergic neurones

Question 56

what effect does amphetamine have?

Answer 56

displaces the NA from its storage vesicles and displaces the direction of the uptake pump, increasing its concentration in the cleft

Question 57

what physiological effects of cocaine and amphetamine?

Answer 57

rapid heart rate, elevated blood pressure and decreased GI motility