Adrenergic Pharmacology

Question 1

Guanethidine

Answer 1

is a false transmitter for NA- and reduces its release

Question 2

NA has a higher selectivity for

Answer 2

alpha, less for beta 1 and even less for beta 2, NA has a higher potency hat beta 2 than adrenaline

Question 3

Adrenaline has a higher selectivity for

Answer 3

beta, and has a higher potency at alpha and beta1 than NA

Question 4

Isoprenaline has no potency at

Answer 4

Alpha

Question 5

Vesicular Transporter

Answer 5

Substrates: Tyramine, Amphetamine, MDMA
Blockers are reserpine and tetrabenazine
NA is stored in small (200nM) and large (400nM) vesicles

Question 6

Neuronal transporter

Answer 6

Substrates: competitive, transported: Amphetamine and Tyramine, MDMA stays in the syntaptic cleft
Inhibitors (are not transported): Cocaine, Methylphenidate(ritalin) and some antidepressants

Question 7

MAO

Answer 7

(MAO) monoamine oxidase – oxidative deamination; inhibited by Phenylenzine- irreversible - increases NA, A, dopamine, 5HT conc in synapse by preventing breakdown
Phenylenzine is used as a antidepressant and anxiolitic
- phenelzine is effective in treating dysthymia,[3] bipolar depression (BD),[4] panic disorder (PD),[5] social anxiety disorder (SAD),[6] bulimia,[7] and post-traumatic stress disorder (PTSD).

Question 8

COMT

Answer 8

Catechol-O-Transferase- tansfers OH group- inhibited by Tolcapone
Tolcapone is selective and reversible.
It is used in the treatment of Parkinson’s, as it reduces the breakdown of L-Dopa by COMT in the periphery and of dopamine in the brain

Question 9

Potency

Answer 9

is a measure of drug activity expressed in terms of the amount of drug required to produce an effect of given intensity- E efficacy

Question 10

Selectivity

Answer 10

refers to the differing affinities with which ligands bind to their binding sites - Ka

Question 11

Selective Alpha1 Agonist

Answer 11

Phenylephrine- used for nasal decongestion (or pupil dilation or increase in bp, through baroceptor reflex can also cause bradycardia)

Question 12

Selective Alpha2 agonist

Answer 12

Clonidine- used to treat high blood pressure, attention deficit hyperactivity disorder, anxiety disorders, withdrawal (from either alcohol, opioids, or smoking), migraine, menopausal flushing, diarrhea, and certain pain conditions. It is classified as a centrally acting α2 adrenergic agonist and imidazoline receptor agonist that has been in clinical use for over 40 years.
Alpha methyl noradrenaline is also alpha 2 selective

Question 13

Salbutamol

Answer 13

Beta 2 agonist - short acting, asthma, and chronic obstructive lung disease

Question 14

Phenoxybenzamine

Answer 14

Non-selective, irreversible, Alpha antagonist -used in the treatment of hypertension, and specifically that caused by pheochromocytoma. It has a slower onset and a longer lasting effect compared with other alpha blockers.

Question 15

Selective Alpha 1 antagonist

Answer 15

Prazosin- to treat high blood pressure and anxiety, PTSD, and panic disorder.
alpha 1 receptors are found,

Question 16

Propranolol

Answer 16

Non-selective Beta antagonist-  to treat high blood pressure, a number of heart dysrhythmias, those with thyrotoxicosis, and essential tremors.[1] It is used to prevent migraine headaches, and further heart problems in those with angina or previous myocardial infarction; 
class 2 antiarrythmic drug

Question 17

Atenolol

Answer 17

Beta 1 antagonist- is developed as a replacement for propranolol in the treatment of hypertension. It works by slowing down the heart and reducing its workload. Unlike propranolol, atenolol does not pass through the blood–brain barrier thus avoiding various central nervous system side effects.
Beta 1 receptors are only in the heart and mediate increase in heart rate and force
used in: Antihypertensive, Cardiac dysrhythmia, Angina, Glaucoma

Question 18

Baroceptor reflex- NA

Answer 18

Noradrenaline activates alpha1 receptors in vasculature, causes vasoconstriction and rise in bp
- vasoconstriction i sensed by baroceptors- baroreflex- vagus nerve - stimulation of musc receptors, decrease in heart rate
NA also directly increases heart rate and force via beta2 rs, but the overall effect is a decrease in heart rate
Adrenaline acts like NA at high conc, bc it preferentially activates alpha receptors then due to a higher potency there

Question 19

Baroceptor Reflex- Isoprenaline

Answer 19

Isoprenaline causes an increase in heart rate and force (CO) due to activation of beta1 receptors in the heart. It also causes a reflex tachycardia via the stimulation of beta2 receptors in the blood vessels which causes vasodilation.
Therefore baroceptor and heart effects are synergistic
Adrenaline acts like isoprenaline at low doses, bc it binds preferentially at beta due to higher selectivity.

Question 20

Anaphylactic shock, Hypotensive crisis

Answer 20

Adrenaline is used which activates beta2 - dilation of bronchi and alpha1 activation which causes vasoconstriction and Beta 1 activation- increase in heart force and rate - baroceptor reflex?