How sex prevents violence: the magic of caress (and GABA)

时间:2013年12月31日 访问次数:3084

Nat Neurosci. 2013 Dec 26;17(1):4-6.

Liming Wang

Long-term exposure to females reduces aggression of male fruit flies. The mechanism involves contact-dependent pheromone sensing and the activation of a small group of GABAergic inhibitory neurons unique to the male brain.
Figure 1 Short-term and long-term interactions with male and female influence male-male aggression in flies: the common theme and potential implications. Left, acute exposure to females enhances male aggression toward other males, whereas chronic exposure to females suppresses male aggression. During chronic exposure to females, certain non-volatile female pheromones (for example, 7,11-HD and 7,11-ND) activate a subset of male gustatory neurons expressing ppk29 and fru, and subsequently employ a small cluster of GABAergic neurons in the male brain coexpressing the serotonin receptor d5HT-1B and fru. These GABAergic neurons likely suppress male aggression by inhibiting downstream aggression-promoting neurons expressing the GABA-A receptor RDL and fru. It would be of interest to examine whether the aggression-promoting effect of acute female exposure employs the same female pheromones and the same gustatory receptor. It is also unclear whether acute female exposure promotes male aggression by activating RDL+ fru+ neurons. Right, exposure to other males acutely enhances male aggression through the detection of a male-specific volatile pheromone cVA by olfactory sensory neurons expressing Or67d. Chronic exposure to other males suppresses male aggression through the same pheromone cVA and the activation of a distinct group of olfactory sensory neurons expressing Or65a. Both groups of neurons are located in the antennae, the primary olfactory organ of fruit flies. These neurons project to the antennal lobes in the brain and innervate with downstream projection neurons at distinct olfactory glomeruli. The central neural circuitry that mediates the opposite behavioral effects of cVA remains unclear. It will be interesting to examine whether the central neural circuitry identified by Yuan et al. (left) is also involved in mediating the opposite effects of cVA on male aggression. AL, antennal lobes; SOG, subesophageal ganglion; CHs, cuticular hydrocarbons.