Instructions Select 2 potential antidotes only from those li

Instructions: Select 2 potential antidotes only from those listed in the box at the bottom.

More than 2 correct answers are possible. For credit you must submit this in class on TUES., Feb. 21 See the 2 sample answers for atropine & physostigmine.

POISON Mode of Action                                        ANTIDOTE

                                                                                                Select 2 from those listed in the box below!

Atropine                              blocks neurotransmitter                                                  (2), (6)

(from belladonna)                      acetylcholine binding to

                                               post-synaptic receptors

Nicotine                                   mimics the action of acetylcholine                                  

(from tobacco)                          in NMJ

Physostigmine                        inhibitor of acetylcholinesterase                                     (4), (5)

(in calabar bean)                       (in NMJ)

Botulinum Toxin [Botox]          blocks vesicles from releasing                                        

(causes botulism)                     acetylcholine into NMJ

Digoxin                                    inhibitor of Na⁺/K⁺ ATPase                                          

(cardiac medication)                pump in axon membrane                       

Black widow venom                  enhances release of acetylcholine into NMJ                    

(latrotoxin)                              by synaptic vesicles

Pufferfish toxin                      blocks closed Na⁺ gates of axon                           

(tetrodotoxin)

NMJ = neuromuscular junction (synapse between neuron & muscle cell)

POTENTIAL ANTIDOTES:

(1) atropine; (2) nicotine; (3) physostigmine; (4) botulinum toxin;

(5) digoxin; (6) black widow venom; (7) pufferfish toxin

Solution

Nicotine - Antidote is Atropine (1) and Pufferfish toxin (6)

Reason : - Nicotine mimics like Acetylcholine, whereas Atropine is Anticholinergic drug. Nicotine opens the voltage gated sodium channels by binding to nicotinic receptors, which are indeed blocked by pufferfish toxin.

Botulinum toxin - Antidote is Physostigmine (3) and Black Window (6).

Reason - The botulinum toxin decreases the levels of AcetylCholine by blocking its release from the vesicles. The antidotes should increase the levels of Acetylcholine. The same thing happens. Physostigmine increases the level of Acetylcholine by inhibiting Acetylcholinesterse enzyme responsible for degradation of Acetylcholine. But Black widow toxin increases the levels of Acetylcholine by enhancing the release of Acetylcholine.

Digoxin - Antidote is Atropine (1) and (3).

Reason :- Digoxin toxicity may cause Bradycardia, which can be treated with Atropine. Physostigmine was used to treat Haert failure by Digoxin toxicity, but now this treatment is obsolete.

Black Widow Venom - Antidote is Botulinum toxin (4) and Atropine(1)

Reason : Black widow venom increases the levels of Acetylcholine. So the antidote is Botulinum toxin which decreases the levels of acetylcholine by blocking its release from the vesicles. Similrly, Atropine blocks binding of Acetylcholine to Nicotinic receptors, thus leading to increased levels of Acetylcholine.

Pufferfish Toxin - Antidote is Nicotine (2)

Reason : Pufferfish toxin is responsible for blociking the voltage gated sodium channels. Nicotine or Acetylcholine binds to Nicotinic receptors and opens the voltage gated Sodium channels.