I need help with the following, I am having trouble finding the answers in the v
ID: 189759 • Letter: I
Question
I need help with the following, I am having trouble finding the answers in the video lecture given to us. Thanks!
1. Tetrodotoxin acts by: A) Blocking potassium channels B) Blocking sodium channels C) Preventing acetylcholine release at the nerve terminal D) Preventing serotonin reuptake
2. Ecstasy has the dual action of increasing release and blocking reuptake of: A) Serotonin B) Dopamine C) Norepinephrine D) All of the above
3. MPTP is metabolized into MPP+ by: A) Astrocytes B) Oligodendrocytes C) Dopaminergic neurons D) Myelin
4. Organophosphate pesticides act by: A) Increasing release of acetylcholine B) Preventing reuptake of acetylcholine C) Mimicking acetylcholine D) Inhibiting acetylcholinesterase
5. Botulinum toxin acts by: A) Blocking release of acetylcholine B) Preventing reuptake of acetylcholine C) Mimicking acetylcholine D) Inhibiting acetylcholinesterase 6. Compounds that cross the blood-brain barrier tend to be: A) Lipophilic B) Non-polar C) Low molecular weight D) All of the above
7. Acetaminophen is metabolized by the following Phase I enzyme: A) Glucuronyl transferase B) CYP2E1 C) CYP3A4 D) None of the above
8. The increased hepatic expression of CYP450 is called: A) Inhibition B) Induction C) Phase I reaction D) Phase II reaction
9. The irreversible lesions that are characteristic of cirrhosis result from deposition of __________ by fibroblasts. A) Epithelial cells B) Lipids C) Bile acids D) Collagen 10. The highest concentration of CYP450 enzyme in the liver are found in: A) Zone 1 B) Zone 2 C) Zone 3 D) Zone 4
11. The reactive intermediate formed when acetaminophen undergoes Phase I metabolism is: A) NAPQI B) Isoniazid C) CYP2E1 D) APAP
12. Vinyl chloride causes a rare form of liver tumor called: A) Cirrhosis B) Hepatocellular carcinoma C) Haemangiosarcoma D) Centrilobular hepatic necrosis
13. The following enzyme is not measured in the serum as an in vivo indicator of liver damage: A) ALT B) NAPQI C) AST D) LDH
Explanation / Answer
1. Option B is correct.
Tetrodotoxin is a Sodium channel blocker. It's a neuro potent. It blocks diffusion of sodium through sodium channel, thus preventing depolarisation and propagation of action potential in nerve cells. Tetrodotoxin acts on central and peripheral nervous systems.
2. Option A is correct.
Ecstasy is a recreational drug that usually consists primarily of 3,4-methylenedioxymethamphetamine (MDMA). The acute effects of MDMA in ecstasy users attributed to increased release and inhibited reuptake of serotonin and norepinephrine . High dose Ecstasy use have been associated with tolerance, depressive symptomatology and persisting cognitive deficits.
3. Option A is correct.
Astrocytes and serotonergic neurons contain MAO-B ( monoamine oxidise -B ) which converts MPTP to MPP+. MPTP itself does not appear to be toxic, but it's oxidized product 1- methyl-4-phenylpyridinium(MPP+) is toxic. It' s by interfering with oxidative phosphorylation in mitochondria by inhibiting complex 1, leading to depletion of ATP and cell death.
4. Option D is correct.
Organophosphate pesticides acts by blocking enzyme acetylcholinestarase leading to build up of acetylcholine in the body causing nervous and respiratory damage that resulting in insect death but also hazardous to humans.
5. Option A is correct.
Botulinum toxin is a neuro toxic protein which prevents the release of neurotransmitter acetylcholine from axon endings at the neuro muscular junction and causes muscle paralysis.
6. Option D is correct.
Low molecular weight, high degree lipid solubility( lipophilic) and non polar substances can cross blood brain barrier by transmembrane diffusion. It is resulted by various processes like activation of hepatic stellar cells and aberrant activity of transforming growth factor beta and it's downstream mediators.
7.Option D is correct.
8. Option A is correct.
9.Option D is correct.
Hepatic cirrhosis is a irreversible process associated with increased and altered deposition of extracellular matrix like collagen in the liver.