Males and females of most species display pronounced sexual dimorphisms. These extend to the nervous systems and include distinct anatomical and functional features, which are ultimately manifested in behavioral differences (Kandel, 2000). It is essential to understand the molecular mechanisms responsible for generating and maintaining these sex-specific differences. We are developing a system in which these mechanisms can be studied in a framework of a well-established model species and a well-characterized group of neurons.
The GABAergic neurons of Caenorhabditis elegans have been studied in hermaphrodites (these animals are genetically equivalent to females of other species), but no in males. We have discovered that the GABAergic system of C.elegans males differs form that of hermaphrodites in two important aspects. First, a number of neurons that are unique to males utilize GABA as a neurotransmitter. Second, several neurons that are common to both sexes utilize GABA in males, but not hermaphrodites. Based on these preliminary findings, we propose a series of experiments to document the extent of sex-specific dimorphism in the GABAergic system of C. Elegans and to investigate the molecular mechanisms responsible for these differences.