Effects of substances that act as stimulants including caffeine, amphetamines and beta agonists on exercise training and performance

Question 1

Ephedrine

- effects

Answer 1

• Increases heart rate, cardiac output, blood pressure
• Bronchodilation
• Hypertension, insomnia, irritability
• Increases anaerobic power output, endurance
• Possibly heart attack, stroke, death
• Pseudoephedrine (form of ephedrine) – found in cold and flu remedies, can lead to a positive doping test

Question 2

what kind of neuron is ephedrine

Answer 2

Noradrenergic neuron

Question 3

Where are some receptors available for ephedrine

Answer 3

pre-synaptic nerve ending

Question 4

Where do adrenaline and noradrenaline have receptors

Answer 4

in the cell membrane

Question 5

What happens when alpha 2 receptors are on the pre-synaptic nerve ending

Answer 5

They act as negative feedback and stops to release of more noradrenaline

Question 6

How does the body control effects of neurotransmitters

Answer 6

• Tissue-specific location of receptor subtypes – heart, liver, skeletal muscle etc.
• Receptor specific affinity of neurotransmitters
• Rapid uptake and metabolism of neurotransmitters
• Alterations in receptor number in certain situations

Question 7

What is the on switch

Answer 7

The action potential and the release of noradrenaline

Question 8

What is the off switch

Answer 8

the removal of neurotransmitters from the synaptic cleft so its not binding to the receptors and also negative feedback

Question 9

Epinephrine/norepinephrine

- alpha 1 receptor

Answer 9

smooth muscle contraction

Question 10

Epinephrine/norepinephrine

- Alpha 2 receptor

Answer 10

Smooth muscle contraction

inhibition of neurotransmitter release

Question 11

Epinephrine/norepinephrine

- Beta 1 receptor

Answer 11

heart muscle contraction

Question 12

Epinephrine/norepinephrine

- Beta 2 receptor

Answer 12

Smooth muscle relaxation

Question 13

What are drugs called which activates a receptor

Answer 13

agonists

Question 14

Which drugs are agonists

Answer 14

• Epinephrine

- norepinephrine

Question 15

Antagonist

Answer 15

A drug which blocks a receptor

Question 16

What drug is ephedrine similar to

Answer 16

Adrenaline

Question 17

What does ephedrine do

Answer 17

it binds to the uptake mechanism, and blocks the receptor, meaning that epinephrine and norepinephrine cant be reuptaken

Question 18

what happens when neurotransmitters cant be reuptakeb

Answer 18

they keep activating the receptor

Question 19

Endogenous structures

Answer 19

• Noradrenalin
• Adrenaline
• Dopamine
• Isoprenaline

Question 20

Clinical use of Adrenoceptor agonists

Answer 20

• Anaphylactic shock (Epinephrine)
• Cardiac Arrest (Epinephrine)
• Asthma (b2)
• Decongestant (b2)

Question 21

Most common asthma treatment

Answer 21

• Salbutamol

Question 22

Asthma &b2-agonist

Answer 22

• Activates the beta-2 receptors in the airways
• Might have some effect on beta-1 at high doses
• Relaxes the smooth muscle here, thus widening the airways and allowing better airflow. Some have suggested that athletes could abuse these to maximise respiratory function

Question 23

Bronchodilators (Beta-2 agonists)

Answer 23

• Asthma or exercise-induced bronchoconstriction often occur because airways becomes too dry or cold, are exposed to allergens or pollutants
• Beta-2 agents are the main way of treating it
• These dilute the airways
• Since specifically bind to beta 2 receptors, tend to have a few side-effects

Question 24

Effect of bronchodilators on exercise performance

Answer 24

• Most studies have shown that, with inhaled bronchodilators like beta 2 agonists, the dose is too low to have any real ergogenic effect
• However, oral bronchodilators given a high systemic dose which can increase muscle strength

Question 25

Clenbuterol

Answer 25

- B2 agonist - Increases muscle strength - Long acting - Clenbuterol is unusual bronchodilator. Alters metabolism - Causes athletes to burn ore fat but promote lean muscle mass

Question 26

Amphetamine | - what does it stimulate

Answer 26

CNS = sympathomimetics

Question 27

Amphetamines | - claims

Answer 27

increase alertness, decrease sensation of muscle fatigue

Question 28

Amphetamine | - dangers

Answer 28

- Physiologic or emotional dependence - Headache, fever, dizziness, tremors - Suppression of normal responses to pain

Question 29

Caffeine

Answer 29

 Ergogenic effects - Proposed mechanism for ergogenic action – increases use of fatty acids, sparing glycogen - May act directly on muscle to enable more prolonged endurance performance

Question 30

Caffeine | - side effects

Answer 30

``` - Nervous irritability  - Muscle twitching  - Psychomotor agitation  - Elevated HR and blood pressure  - Increased occurrence of premature ventricular contraction  - Insomnia ```

Question 31

What does adenosine do

Answer 31

acts on receptors to decrease HR and cause vasodilation

Question 32

What has an inhibitory effects in the CNS

Answer 32

Adenosine

Question 33

What are caffeine's stimulatory effects primarily due to

Answer 33

Its inhibitions of adenosine by binding to the same receptors

Question 34

what does the reduction in adenosine activity lead to

Answer 34

increased activity of the neurotransmitter dopamine