Anandamide is a lipid-based molecule that acts as an endogenous ligand of CB1 receptors.

• A. True
• B. False
• C. Lipid-based but not endogenous
• D. Endogenous but not lipid-based

Answer: (A)

Anandamide is part of the body's own signaling system and is a lipid-derived molecule. It is produced on demand in neurons (endogenous) and travels to CB1 receptors, which are abundant in the brain, where it acts as a messenger to modulate neurotransmitter release. Its lipid nature allows it to diffuse through membranes and function as a retrograde signal at synapses. This combination—being endogenous and lipid-based—fits exactly with the statement, making it true. For context, endocannabinoids like anandamide and 2-AG serve to fine-tune synaptic activity by binding to CB1 receptors and dampening neurotransmitter release, and they are distinct from externally administered or non-lipid signaling molecules.