Sympatholytics

Question 1

Peripheral nervous system is divided into which 3 sub-systems

Answer 1

Sensory
Somatic motor
and
Autonomic system

Question 2

What is the role of sensory system

Answer 2

To transmit information to the CNS

Question 3

What is the role of Somatic motor system

Answer 3

To control the skeletal muscles

Question 4

What is the role of Autonomic system?

Answer 4

To control the glands, heart and smooth muscles

Question 5

Autonomic system is further divided into which two systems?

Answer 5

Sympathetic - activated during critical situations
and
Parasympathetic - activated at rest

Question 6

What do Adrenoblockers do? (Adrenergic receptor antagonists)

Answer 6

Interact with adrenergic receptors and occupy these sites
-> therefore not allowing access to adrenergic agonists

Question 7

What do nonselective B1-B2 blockers do?

Answer 7

Inhibit the B1-cardiac stimulant effects of sympathomimetics
Also block B2 depressor response to the mimetics

Question 8

What are a-adrenoblockers antagonists to?

Answer 8

Adrenaline and noradrenaline

Question 9

What is “ergot fungus”

Answer 9

A parasitic fungus found in grains that includes a mixture of alkaloids - one of which is lysergic acid -> Causes poisoning

Question 10

What are the symptoms of severe ergot alkaloid poisoning?

Answer 10

Strong hypotension, gangrenous necrosis of tissues

Question 11

What are some symptoms of chronic ergot alkaloid poisoning - or Ergotism?

Answer 11

Weakness, nausea, headache, vasoconstriction and gangrene

Question 12

What are some cardiovascular effects of ergot alkaloids?

Answer 12

Intense spasm of peripheral blood vessels (due to effect on smooth muscle of blood vessels)
Higher dose causes hypotension and central blood vessels
Larger doses block a1 receptors

Question 13

What are some effects of ergot alkaloids on the nervous system or respiratory centre

Answer 13

Initially CNS stimulation, thereafter deep depression
and Inhibition of respiratory centre
Vomiting
Rhythmic contractions of uterus (may even tear)

Question 14

Generally what do alpha blockers do?

Answer 14

Block both presynaptic and postsynaptic a1 and a2 adrenergic receptors

Question 15

3 directions of the effect of phentolamine?

Answer 15

1. Adrenoblocking activity
   -Stimulation of heart
2. Parasympathomimetic activity
   -Stimulation of GI tract
3. Histamine-like effect
   -Secretion of stomach + dilation of peripheral blood vessels

Question 16

What is the mechanism of action of Phentolamine?

Answer 16

It competes with mediator noradrenaline by inhibiting its binding with the receptors

Question 17

What are some side effects of phentolamine?

Answer 17

Over-stimulation of heart and GI tract - causing arrhythmia and diarrhea

Question 18

Where can alpha blockers localise and why?

Answer 18

In adipose tissue because of their relatively high fat solubility

Question 19

Mechanism of action of B-adrenoblockers

Answer 19

Direct selective blocking of B-receptors.
B-effects from sympathetic innervation of organs will cease

Question 20

When should you not use non-selective Beta blockers, and why?

Answer 20

In case of asthmatic issues or allergic reactions
Because mixed B-blockers inhibit the relaxation of bronchial muscles and cause constriction

Question 21

What are some clinical uses of B-blockers ?

Answer 21

Hypertension
Ischemic heart disease
Myocardial infarction
Migraines
Arrhythmias
In cases of Weakened heart muscle and chronic heart failure

Question 22

How are B-blockers useful in ischemic heart disease?

Answer 22

They reduce the heart’s workload and improve the working capacity of the heart

Question 23

How are B-blockers useful in arrhythmias?

Answer 23

They eliminate the effect of the sympathetic nervous system on the conduction system and automaticity of the heart

Question 24

What is the function of reserpine?

Answer 24

It inhibits the uptake of the mediator noradrenaline into storage vesicles
Noradrenaline synthesised from dopamine will remain available and will be broken down by MAO
>Arterial pressure decreases and pressure increasing effector mechanisms are depressed

Question 25

How does Methyldopa work?

Answer 25

It prevents the conversion of DOPA into dopamine and noradrenaline - therefore inhibiting the synthesis of noradrenaline