Alissa M. Rodriguez Rodriguez, Joseline M. Velazquez Cintron and Zaira Mateo Mayol
Alzheimer’s disease is a neurodegenerative disease characterized by the extracellular aggregation of β-amyloid plaques and tau protein entanglements. The accumulation of these β- amyloid plaques leads to progressive neural death, displaying as a decline in memory and cognitive function. Melatonin, a hormone produced by the body in the pineal gland, has been proven to act as a neuroprotector due to its antioxidant properties. For this reason, it is suspected that melatonin can help alleviate these toxic neurological symptoms shown in Alzheimer’s patients. In this study, wild-type Caenorhabditis elegans (C. elegans) N2 was used to study the effects of commercial melatonin regarding its associative memory. This animal model is ideal due to its wellknown nervous system and memory retention. The worms were divided into a control group (with no prior exposition to commercial melatonin) and an experimental group (with prior exposition to commercial melatonin).
A chemotaxis assay was performed to see if commercial melatonin enhanced the associative memory exhibited in C. elegans by associating an odorant (diacetyl) with food (E. coli K12). A large petri plate was divided into three areas: 5 μL diacetyl, 5 μL distilled water, and origin with 100 μL of M9 containing C. elegans (n = 100-200). To quantify the worms in the distilled water and diacetyl regions, sodium azide (0.5 M) was added into the solutions. Once the worms were placed in the origin, the arrival to the diacetyl and distilled water areas was observed over a period of one hour in 10-minute intervals. By associating diacetyl to E. coli K12, the worms will feel more attracted to it, while being less attracted to distilled water. The experimental group presented a larger scale of associative memory with a chemotaxis index of +1, in comparison to the control group with a chemotaxis index of +0.93. Our preliminary results demonstrate that commercial melatonin enhances memory in C. elegans.