Pheromone signals from dominant males stimulate the production of new neurons in the olfactory bulb and hippocampus of the brain in female mice, reports a paper in the August 2007 issue of Nature Neuroscience. This neurogenesis appears to be necessary for the normal female preference to mate with dominant males.
Pheromones are chemical cues that female mice use to recognize and select their mates. In the present study, Samuel Weiss and colleagues report that pheromones from dominant males, but not from subordinate or castrated males, stimulated the production of neurons. Females with damage to the main olfactory system did not show neurogenesis in response to pheromones. Male pheromones are known to stimulate the release of luteinizing hormone and prolactin in females. Luteinizing hormone mimicked the effect of male pheromones in the dentate gyrus of the hippocampus, while females lacking the receptor for this hormone did not respond to male pheromones. Similarly, prolactin increased neurogenesis in the olfactory bulb, and females lacking the receptor for prolactin did not respond to pheromones.
Disrupting neurogenesis during initial exposure to the pheromone eliminated a female's subsequent preference for the dominant male, though the females were still able to detect novel odours and showed normal locomotor behaviour. The authors conclude that the birth of new neurons may be important for female reproductive success.
Samuel Weiss (University of Calgary, Alberta, Canada)
Additional contact for comment on paper:
Zhengui Xia (University of Washington, Seattle, WA, USA)
Abstract available online.
(C) Nature Neuroscience press release.
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