Drug Interactions With Receptors And Ion Channels

Question 0

Atropine

Answer 0

From Atropa belladonna, competitive antagonist of mAChR. Parasympatholytic.

Question 1

Adenosine

Answer 1

Purine nucleoside. Four receptor subtypes, all GPCRs: A1 (Gi/o), 2A (Gs), 2B (Gs) and A3. Promotes sleep, suppresses arousal, vasodilatation.

Question 2

Bay K 8644

Answer 2

Calcium channel agonist. Research tool. +ve inotropic.

Question 3

Benzilylcholine choline

Answer 3

Irreversible inhibitor of mAChR. Investigate relationship between receptor occupancy and response.

Question 4

Benzocaine

Answer 4

Inhibits voltage-dependent sodium channels on nerve. Stops AP. Local anaesthetic.

Question 5

Alpha-bungarotoxin

Answer 5

Snake venom. Irreversible competitive inhibitor of nAChR at NMJ. Paralysis, respiratory failure and death.

Question 6

Cholera toxin

Answer 6

Causes CFTR activity. Secretion of ions and water into intestinal lumen. Rapid loss of fluid. Severe dehydration.

Question 7

Diltiazem

Answer 7

Calcium channel blocker. Potent vasodilator, increase heart blood flow. Negative inotropic effect. Hypertension, angina and arrhythmia.

Question 8

d-tubocurarine

Answer 8

nAChR antagonist. Skeletal muscle relaxant in anaesthesia.

Question 9

Ethinylestradiol

Answer 9

Derivative of endogenous oestrogen. Acts on oestrogen receptor. Used in combined pill.

Question 10

Glibenclamide

Answer 10

Anti diabetic drug. Binds to KATP and activates inhibitory subunit. Caused insulin release via depolarisation

Question 11

Isoprenaline

Answer 11

Beta 1 and 2 agonist. Positive chromite optic and inotropic effects. Used to treat asthma

Question 12

Lidocaine/lignocaine

Answer 12

Blocks fast voltage gated sodium channel in cardiomyocytes and neurones. Local anaesthetic.

Question 13

Minoxidil

Answer 13

Nitric oxide agonist. Vasodilator. Anti hypertensive. Also promotes hair growth - used in androgenic alopecia.

Question 14

Nicorandil

Answer 14

Stimulates cGMP production. Activates KATP hyper polarising cell and reducing [Ca2+]i. Smooth muscle relaxation and vasodilatation due to nitrate group.

Question 15

Nifedipine

Answer 15

L-type calcium channel blocker. Antianginal and anti hypertensive. Primary treatment for African American patients.

Question 16

Norethisterone

Answer 16

Progestogen agonist. Treats PMS, painful/heavy periods.

Question 17

Pertussis toxin

Answer 17

Causes whooping cough. Bonds to receptor - interferes with cell signalling, causes insulin release and inhibits immune responses. Could treat hypertension, autoimmunity.

Question 18

Prednisolone

Answer 18

Cortisol derivative irreversibly binds to alpha and beta glucocorticoid receptors. Changes gene transcription. Treats inflammatory and auto-immune conditions.

Question 19

Quinidine

Answer 19

Blocks fast inward sodium current. Causes increase in AP and QT duration. Used dependent block. Used as an antiarrhythmic.

Question 20

Spironactone

Answer 20

Antagonist of mineralocorticoid and androgen receptor. Potassium soaring diuretic and antihypertensive.

Question 21

Tamoxifen

Answer 21

Antagonist to oestrogen receptor. Prodrug metabolised in liver. Used in endocrine therapy for certain breast cancer.

Question 22

Tetrodotoxin (TTX)

Answer 22

From pufferfish. Binds to VGCC, block AP firing. Toxic - paralysis of voluntary muscles, respiratory failure and loss of vagal regulation of HR.

Question 23

Tyrphostins

Answer 23

Tyrosine kinase inhibitor (eg inhibit EGFR activity). Anti-cancer drug.

Question 24

Verapamil

Answer 24

Preferentially block L-type Ca2+ channels in cardiac muscle. Use dependent. Hypertension, angina and antidysrhythmias (class IV).