Pharmacology of Adrenaline and Other Neurotransmitters

Questions and Answers

What happens to glucuronides in the GI tract?

They are reabsorbed into the bloodstream

They are hydrolysed by B-glucuronidase (correct)

They are excreted into the bile

They are metabolized by the liver

Tetracyclines should be avoided in pregnant people and young children because they have a high affinity for calcium.

True

What is the enzyme responsible for metabolizing ethanol?

alcohol dehydrogenase

Activated charcoal prevents aspirin overdose by decreasing aspirin absorption as it has ______________ that the drug molecules attach to.

pores on its surface Signup and view all the answers

Which of the following is an example of a zero-order kinetics drug?

Ethanol Signup and view all the answers

Match the following drug transporters with their types:

MDR1 = ATP-binding cassette (ABC) OAT1 = Solute carrier transporters (SLC) BCRP = ATP-binding cassette (ABC) MRP2 = ATP-binding cassette (ABC) Signup and view all the answers

Thiopental is commonly used for anesthesia maintenance.

False Signup and view all the answers

What is the mechanism of action of ritonavir as a CYP inhibitor?

irreversible inhibition of an enzyme due to formation of a complex between the enzyme and reactive metabolite via covalent bonding Signup and view all the answers

What is the action of Salbutamol?

Agonist at β2-adrenoceptors for bronchospasm relief Signup and view all the answers

Paracetamol is an analgesic that inhibits cyclooxygenase.

True Signup and view all the answers

What is the mechanism of action of Nifedipine?

Ca2+ channel blocker Signup and view all the answers

Fluoxetine is an antidepressant that works by ______________ serotonin re-uptake.

inhibiting Signup and view all the answers

Match the following antifungal drugs with their mechanism of action:

Echinocandin = Inhibiting cell wall synthesis Polyenes = Altering cell membrane integrity or permeability Azoles = Inhibiting ergosterol biosynthesis Signup and view all the answers

What is the mechanism of action of Amphetamine?

Using noradrenaline transporter to enter nerve terminals and replace/release the neurotransmitters noradrenaline and serotonin Signup and view all the answers

Teratogens are agents that cause birth defects.

True Signup and view all the answers

What is the mechanism of action of Chloramphenicol?

Inhibiting bacterial protein synthesis Signup and view all the answers

Ritonavir is a potent ______________ inhibitor used to boost protease inhibitors.

CYP3A4 Signup and view all the answers

What is the mechanism of action of Morphine?

Activating opioid receptors Signup and view all the answers

Study Notes

Adrenergic receptors

Adrenaline acts on β-adrenoceptors, increasing contractility
α1, α2, and muscarinic acetylcholine receptors have different actions
β-adrenoceptors activate adenylate cyclase
Salbutamol is an agonist at β2-adrenoceptors, relieving bronchospasm
Mechanism of salbutamol action: binds to β2-adrenoceptor, activates Gs protein, increases adenylate cyclase, and relaxing smooth muscle

Other receptors and drugs

Acetylcholine acts on muscarinic receptors, stimulating nicotinic receptors
Noradrenaline acts on α-adrenoceptors, mimicking endogenous ligands
Phenylephrine activates α-adrenoceptors, causing vasoconstriction
Diphenhydramine binds to histamine and muscarinic acetylcholine receptors
Pancuronium is a nicotinic receptor antagonist, used for muscle paralysis
Insulin activates insulin receptors, lowering blood glucose
Prednisolone is a glucocorticoid drug, activating nuclear receptors
Nifedipine blocks Ca2+ channels, treating hypertension
Benzodiazepines enhance GABA-activated Cl- channel opening, treating anxiety
Paracetamol inhibits cyclooxygenase, an analgesic
Fluorouracil blocks DNA synthesis, an anti-cancer drug
Ciclesonide is a prodrug, converted to an active metabolite in the lung
Fluoxetine inhibits serotonin re-uptake, an antidepressant
Amphetamine uses noradrenaline transporters, releasing neurotransmitters
Ethanol increases drug metabolism, leading to lower plasma concentrations

Neurotransmitters

GABA is an inhibitory transmitter, forming from glutamate
Types: GABAa, GABAb (GPCR), GABAc (ion channel receptors)
Glycine activates ion channel receptors, an inhibitory neurotransmitter
Glutamate activates ion channel receptors, an excitatory neurotransmitter
5-HT activates ion channel receptors, increasing motility and vasodilation
Suxamethonium is a long-acting agonist, causing neuromuscular block

Teratogens and adverse drug reactions

Teratogens: agents causing birth defects by altering fetal growth
Type A ADR: linked to pharmacological effects, showing a dose-response relationship
Type B ADR: idiosyncratic, unpredictable adverse reactions
Type D ADR: time-related, occurring after drug use
Type F ADR: unexpected failure of drugs to produce therapeutic effects
TOCP causes delayed neuropathy, a human teratogen
Diethylstilbestrol is a synthetic estrogen, linked to severe birth defects
Thalidomide causes severe birth defects, a human teratogen
Fetal alcohol syndrome results from prenatal alcohol exposure

Antibiotics and antifungals

Penicillin inhibits bacterial cell wall synthesis
Amoxicillin is a broad-spectrum penicillin, not β-lactamase resistant
Clavulanic acid is a β-lactamase inhibitor, semisynthetic
Augmentin is a combination drug for penicillin resistance
Cephalosporin inhibits bacterial cell wall synthesis
Aminoglycosides inhibit bacterial protein synthesis, inhibiting initiation
Tetracyclines inhibit bacterial protein synthesis, inhibiting tRNA binding
Amphenicols inhibit bacterial protein synthesis, inhibiting transpeptidation
Antifungal macrolides inhibit protein synthesis, preventing tRNA transfer
Echinocandin inhibits fungal cell wall synthesis
Polyenes alter fungal cell membrane integrity
Allylamines alter fungal cell membrane integrity
Azoles inhibit ergosterol biosynthesis, altering fungal cell membrane integrity

Enzymes and transporters

CYP2D6 inhibitor: cimetidine
Prodrug example: codeine -> morphine (dealkylation)
Tenofovir disoproxil is a prodrug, hydrolyzed to tenofovir by esterase
Morphine is metabolized to morphine-3-glucuronide (major) and morphine-6-glucuronide (minor) by UGT2B7
Enterohepatic recirculation: lipophilic drug undergoes absorption, hepatic metabolism, conjugation, excretion into bile, and reabsorption
Paracetamol is metabolized to NAPQI by GST

Important notes

Charcoal prevents aspirin overdose by absorbing the drug, preventing reabsorption
Sodium bicarbonate prevents salicylate overdose by alkalising urine, increasing ionization, and facilitating excretion
Important ABC transporters: MDR1, MRP2, BCRP
Important SLC transporters: OAT1, OAT3
Ethanol is stored in total body water and metabolized by alcohol dehydrogenase
Tetracyclines have high affinity for calcium and should be avoided in pregnancy and young children
Thiopental is not used for anesthesia maintenance due to its lipophilic properties and potential for 'hangover' effect

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Description

This quiz covers the pharmacological actions of adrenaline, acetylcholine, noradrenaline, and phenylephrine on different receptors and their effects on various physiological processes.