The influence of gender and gonadal hormones on neuronal development is now known to extend beyond those neuronal systems directly involved in the control of reproductive functions. For example, the nigrostriatal dopamine (DA) system has been found to be both sexually dimorphic and sensitive to steroid hormones. In contrast, testicular hormones do not influence striatal-mediated behaviors or striatal DA release in male rats. However, estrogen can modulate the behavioral response to dopaminergic drugs in both sexes. This sex difference is not dependent on the presence of androgens during the neonatal period but instead develops later in the female, perhaps in association with puberty. More recent experiments from this lab suggest that estrogen can act directly in the striatum to improve sensorimotor performance and to stimulate DA release from the striatum of female rats (but not males). Experiments proposed will examine organizational and activational influences of estrogen in the striatum and striatal mediated behaviors. Specific questions to be addressed include: 1) Is the striatum preferentially sensitive to pulsatile stimulation with estrogen?; 2) Can other steroid hormones influence striatal DA activity?; 3) Where and how does estrogen act in the striatum?; and 4) What is the role of hormones during development on the expression of sex differences in the nigrostriatal system of adult rats? Behavioral and neurochemical approaches will be integrated to address these questions. The involvement of the gonadal steroid hormones in the modulation of striatal DA activity may be important for our understanding of the extrapyramidal system and treatment of its disorders. For example, in some women choreiform disorders have been found to develop during periods of elevated gonadal steroids such as during pregnancy or with use of birth control pills. In addition, estrogen has been found to influence the symptoms of tardive dyskinesia. However, our understanding of how estrogen influences neural activity in the striatum is still very limited. It is necessary to better understand the basic mechanisms involved before all of the clinical applications will be appreciated.
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| Becker, J B; Cha, J H (1989) Estrous cycle-dependent variation in amphetamine-induced behaviors and striatal dopamine release assessed with microdialysis. Behav Brain Res 35:117-25 |
