Question

Given below are two statements:
Statement I: Macrocyclic lactone (ivermectin) is not effective against trematodes and cestodes
Statement II: The inhibitory neurotransmitter present in trematodes and cestodes is glycine
In the light of the above statements, choose the most appropriate answer from the options given below

• A. Both Statement I and Statement II are true
• B. Both Statement I and Statement II are false
• C. Statement I is correct but Statement II is false
• D. Statement I is incorrect but Statement II is true

Hint:

Ivermectin Spectrum: Highly effective against NEMATODES and ARTHROPODS (targets GluCl/GABA channels). Completely INEFFECTIVE against Trematodes and Cestodes.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Anthelmintic pharmacodynamics: macrocyclic lactones selectively target invertebrate glutamate-gated chloride channels (GluCl) and GABA receptors present in nematodes and arthropods but absent in platyhelminths.

Step 2: Detailed Explanation:
1. Statement I: Macrocyclic Lactones (Ivermectin, Doramectin, Moxidectin) bind with high affinity to glutamate-gated chloride channel (GluCl) receptors and GABA-gated chloride channels, causing hyperpolarization and flaccid paralysis in nematodes and arthropods. Trematodes (flukes) and Cestodes (tapeworms) completely lack these glutamate-gated chloride channels; hence, ivermectin is ineffective against trematodes and cestodes. Statement I is correct.
2. Statement II: Platyhelminths (trematodes and cestodes) use Serotonin (5-HT) as their primary excitatory neuromuscular neurotransmitter and Acetylcholine (ACh) FMRFamide-related peptides as inhibitory neurotransmitters, not glycine. Statement II is false.

Step 3: Final Answer:
Hence, Statement I is correct but Statement II is false, matching option (C).