Steroid Hormone Lab Report

Decent Essays
Specific Aim The female gonadal steroid estrogen has been shown to suppress homeostatic feeding and body weight by its action in the arcuate nucleus, ventromedial hypothalamus, paraventricular nucleus, nucleus of the solitary tract, and dorsal raphe. There is also evidence that in female rodents, estrogen can influence behaviors associated with food reward which are known to be regulated by the mesolimbic dopamine system. However, the precise locations or mechanisms of action within the mesolimbic system through which estrogen influences food reward are not known. I hypothesize that in female rats, estrogen signaling through ERβ in the VTA and/or NAc suppresses palatable food reward. Background In female rats, food intake and body weight vary across the ovarian cycle and are lowest during proestrus and…show more content…
This system consists of dopamine (DA) neurons in the ventral tegmental area (VTA) and their efferent projections to areas such as the nucleus accumbens (NAc) and prefrontal cortex (PFC). It has been shown that the presentation of food, or food-associated cues, stimulates DA release in NAc[14,15], and this DA is necessary to facilitate motivated behavior[16]. Both the VTA and NAc express estrogen receptors (ER) [17], and both regions respond to ovarian cyclicity such that the activity of VTA DA neurons [18] and NAc DA content [2] are depressed during proestrus. Furthermore, peripheral estrogen treatment has been shown to increase VTA D3R mRNA levels [19], decreases VTA TH immunoflourescence[20], decrease stimulated DA release in NAc [21], and to prevent OVX-induced decrease in NAc D2R[22]. From this, it appears that estrogen has the capacity to depress mesolimbic DA signaling and therefore it is possible that estrogen can decrease the rewarding properties of palatable food, decrease the motivation to acquire food, and subsequent
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