Prolactin promotes the recruitment of main olfactory bulb cells and enhances the behavioral exploration toward a socio-sexual stimulus in female mice.

Area of Science:

• Neuroscience
• Endocrinology
• Animal Behavior

Background:

• Olfactory communication relies on pheromones processed by main and accessory olfactory systems.
• Prolactin receptors are present in these systems, suggesting a role in olfactory processing.
• Previous work indicated prolactin's involvement in female olfactory bulb maturation.

Purpose of the Study:

• Investigate prolactin receptor expression during sexual maturation.
• Examine prolactin's direct effects on pheromone response.
• Assess prolactin's impact on female behavior and neural activation.

Main Methods:

• Measured prolactin receptor expression in olfactory bulbs across maturation stages.
• Administered prolactin to female mice and exposed them to male pheromones.
• Analyzed neural activation (cFos) in olfactory bulbs and brain relays.
• Investigated intracellular pathways (ERK) in the olfactory bulb.

Main Results:

• Prolactin receptor expression was constant in the main olfactory bulb but decreased in the accessory olfactory bulb with maturity.
• Prolactin administration increased female exploration of male stimuli.
• Prolactin enhanced cFos activation in the amygdala and olfactory bulb glomeruli, particularly in the main olfactory bulb's mitral cells.
• The ERK pathway was upregulated in the main olfactory bulb upon pheromone exposure.

Conclusions:

• Prolactin plays a role in processing chemosignals in female mice.
• Prolactin appears to activate the main olfactory system while reducing the vomeronasal response to pheromones.
• These findings highlight prolactin's influence on social behavior and olfactory processing.