The common fatty acids have a pheromone-like effect, improving the emotion in mice

Abstract

Fatty acids widely exist in some exocrine organs such as mammary glands, sweat glands and vaginas of mammals and have been exemplified to be appeasing pheromones in mammals. Here, we tested the possibility that fatty acids are common pheromones in mammals using mice that had few fatty acids in the main pheromone sources (eg.urine and preputial glands) of known pheromones. Five synthetic fatty acids were equally mixed to form a blend (MA) to be tested and a blend (MP) of hexadecanol and hexadecanol acetate of two identified male pheromones of mice was used as a control. Both MA and MP activated typical brain regions to perceive pheromones via. immunohistochemical staining. The numbers of c-Fos+ neurons activated by MA vs. MP were greater in the AOB and BNST, equal in VMH and smaller in the BLA. Chronic exposure to either MA or MP significantly reduced isolation-induced anxiety and improved sociality and exploring behavior. Especially, the mRNA expression of some behavior-related genes such as BDNF, GluN2B, DRD2, ERβ and 5HT2A was increased or showed a tendency to increase in hippocampus or mPFC of the mice after chronic exposure to either MA or MP. Our results suggested that some fatty acids might be common pheromones probably from the exocrine organs found in all mammals.