Question

please help with part I and ii

(b) According to the CDC, atropine and pralidoxime are antidotes for sarin toxicity (1)Briefly explain why atropine can be used as an antidote. (ii) Draw a chemical mechanism to demonstrate how pralidoxime chloride acts as an antidote. Me pralidoxime

Answer 1

2) i) Atropine blocks the action of a certain chemical that may reach high levels in the body after a poisoning. Atropine also stimulates the heart and reduces the secretions of the nose, mouth, and lungs to improve breathing. Pralidoxime reverses muscle weakness or paralysis caused by a poison or nerve agent.Atropine and pralidoxime is a combination medicine used as an antidote to treat poisoning by a pesticide (insect spray) or a chemical that interferes with the central nervous system, such as nerve gas. Atropine alleviates the symptoms brought on by nerve gas exposure by blocking the acetylcholine receptors. That way, even though the chemical attack causes an overabundance of acetylcholine in a victim's brain, the receptors do not pick up the signals and the person's nervous system has a chance to even itself out. Atropine is an enantiomeric mixture of d-hyoscyamine and l-hyoscyamine, with most of its physiological effects due to l-hyoscyamine. Its pharmacological effects are due to binding to muscarinic acetylcholine receptors. It is an antimuscarinic agent.

ii) Pralidoxime is typically used in cases of organophosphate poisoning. Organophosphates such as sarin bind to the hydroxy component (the esteric site) of the active site of the acetylcholinesterase enzyme, thereby blocking its activity. Pralidoxime binds to the other half (the unblocked, anionic site) of the active site and then displaces the phosphate from the serine residue. The conjoined poison / antidote then unbinds from the site, and thus regenerates the fully functional enzyme. Some phosphate-acetylcholinesterase conjugates continue to react after the phosphate docks to the esteric site, evolving into a more recalcitrant state. This process is known as aging. Aged phosphate-acetylcholinesterase conjugate are resistant to antidotes such as pralidoxime. Pralidoxime is often used with atropine (a muscarinic antagonist) to help reduce the parasympathetic effects of organophosphate poisoning. Pralidoxime is only effective in organophosphate toxicity. It has no beneficial effects if the acetylcholinesterase enzyme is carbamylated.

- bond formation 2-PAM PTOR bond R, dissolution Sites "Anionic Serine "Esteric Site" Acetylcholinesterase