Stearoyl-Coa Desaturases Sustain Cholinergic Excitation and Copulatory Robustness in Metabolically Aging <i>C. elegans</i> Males

Abstract

Regulated metabolism is required for behavior during adult aging. To understand how lipid usage affects motor coordination, we study male C. elegans copulation as a model of energy-intensive behavior. Copulation performance drops after 48 hours of adulthood. Interestingly, we found that ~12-24 hours before behavioral decline, males prioritize exploring and copulation behavior over feeding, suggesting that catabolism of lipid stores occurs during this period. To investigate how over-catabolizing consumed fats and perturbing lipid storage affects mating, we studied the copulation behavior and neural calcium transients of fat-6(lf); fat-7(lf) stearoyl-CoA desaturase mutant males. In wild-type males, intestinal and epithelial fat-6/7 expression increases during the first 48 hours of adulthood. The fat-6(lf); fat-7(lf) behavioral and metabolic defects indicate that in aging wild-type males, the increased expression of stearoyl-CoA desaturases in the epidermis modulates the levels of EAG- family K+ channels in the reproductive cholinergic neurons and muscles to sustain behavior.