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
The hypothalamus is thought to have quite a lot of control over our eating behaviour, the lateral hypothalamus (LH) is considered to be the feeding switch that makes an individual begin to feed whereas the ventromedial hypothalamus (VMH) is the satiety switch that makes an
In this experiment, contractions of the earthworm gut are measured in an organ bath with a force transducer. The effect of neurotransmitters and ionic concentrations on contraction strength and rate will be investigated.
The activity of VTA DA neurons has been associated with a variety of behaviors, including reward, salience, aversion, and novelty. VTA neurons differ in their molecular and electrophysiological properties, and differ in their axonal projections and inputs and this has been suggested to be the underlying principle guiding the ability of the VTA to modulate such diverse behaviors (Margolis et al., 2006, Lammel et al., 2008). Intake or presentation of food or food-associated cues activates DA neurons and stimulates DA release in the Acb (Hernandez and Hoebel, 1988, Park and Carr, 1998, Hajnal and Norgren, 2001, Roitman et al., 2004) and is associated with the acquisition of food reward, suggesting that these stimuli activate VTA DA neurons involved in the encoding of reward. Alpha-MSH action in the VTA also increases DA release in Acb and PFC (Torre and Celis, 1986, 1988, Lindblom et al., 2001, Sanchez et al., 2001, Jansone et al., 2004, Yang and Shieh, 2005), yet acts to decrease feeding (Roseberry, 2013, Yen and Roseberry, 2014). This suggests that alpha-MSH results in activation of DA neurons different from those which encode reward. Determining the identity of MC3R-expressing VTA neurons and identifying synaptic circuitries in which these neurons participate is necessary to begin unraveling the mechanisms by which melanocortins act on the mesolimbic dopamine system to
It was found that energy expenditure correlated to the fluctuations in E1 and progesterone in that there was a significantly lower energy expenditure during a 24-hour measurement during the follicular phase when compared to the menstrual (~3.8%) and luteal (~4.9%) phases.12 Interestingly, this study also found that expenditure while asleep was significantly greater during the luteal phase than during the menstrual and follicular phases which is a direct correlation to an increase in progesterone. As a result of this study, it was concluded that fluctuations of hormones throughout the menstrual cycle significantly affects energy expenditure, notably during sleep, but also in overall BMR.12 This can be linked directly to fluctuations in progesterone and can be observed when measuring energy expenditure and BMR over a 24-hour
Steroids are being produced inside the human body in every day mannerism. There are some steroids which occur naturally inside our body and they are estrogen in women, testosterone in men. Scientists have found benefits of these hormones by reproducing the chemicals synthetically in the lab. These compounds produce the same results as with the natural hormones. Synthetic or manmade steroid have various medical uses. These compounds will come in various forms like pills, injections, cream or eye drops. They will decrease inflammation. They will also promote lean tissue growth. They are also able to increase appetite. If you know that someone has seriously ill or injured, then steroids might helped them
Dopaminergic neurons are less than 1% of the entire number of neuronal population in the brain. These neurons have specific influence on brain function. For example, there are modifications of synaptic plasticity happens due to learning and memory as a result of the activity of the metabotropic dopamine receptors. Learning is a change in responsiveness to a particular stimulus whereas memory is the cellular modification that mediates that change. In this regard, recent evidence indicates that DA is involved in reward-related incentive learning.
It seems as though throughout the years, the usage of steroids has always been to enhance your performance, whether that be for a sport or body mass and muscle strength in general. I find this chapter in Psychology interesting, because It goes hand and hand with Anatomy, which I am currently learning. I would like to further explore the basics on where our body produces natural steroids, the effects on the endocrine and reproductive system due to steroid use, and lastly, the damage steroid use can have on your mentality.
ERs are co-expressed by the majority of enkephalin neurons in the superficial laminae of the dorsal horn in female rats (Amandusson & Blomqvist, 2010). Estradiol
to produce hormones that are beneficial to the activation of others parts of the brain and body. (Berger 201, pgs. 217-219)
Corticosteroids are a part of the steroid hormones family, which include glucocorticoids that are synthesized and secreted by the adrenal cortex (Simon, et al., 2013, p. 545). On the flipside anabolic steroids are controversial drugs that are synthetic variants of testosterone (Simon et al., 2013, p. 45).
Looking aesthetic can happen naturally; however, that naturally average person cannot reach superhuman levels like the greatest athletes--without illegal drugs anyways. Genetically speaking, each person has their own traits which allows certain people to have bodies like Arnold Schwarzenegger or that of a fourth grader. In fact, the muscles in the our bodies has its natural limits. With the use of anabolic steroids--that are illegal--the natural limits are pushed beyond that state regardless of genetics. Role Models such as Arnold Schwarzenegger, Barry Bonds, and Lance Armstrong showcase their unbelievable perfect athleticism through their immeasurable accomplishments with the supplementation of steroids. Moreover, this leads to influential desires. After all, who does not want to be Schwarzenegger, perform like Bonds, or even Armstrong? Accordingly, with these athletes using these steroids, desires arise in everyday people as they look for short term results, rather than health consequences due to side effects. No one should use illegal substances for an advantage just
Sherry Baker’s article “The Home Team Advantage...and Other Sex Hormone Secrets” aims to summarize the research on what different amounts of the sex hormones, testosterone and estrogen, actually do to us. Baker looks at behaviors in low-testosterone and high-testosterone males, how prenatal exposure to testosterone influences spatial reasoning, and memory capabilities in relation to estrogen levels.
However recent research shows that the process is more complicated. Dopamine is not only related to pleasure but also to learning and memory, key components in going from liking a substance to becoming addicted to it. According to this theory it is believed that dopamine combines with another neurotransmitter, glutamate, to take over the brain’s system of reward related learning. This system plays an important role in sustaining life by linking such activities as eating and sex with pleasure and reward.
Brain structure that produces hormones that control body temperature, hunger, moods, and sex drive is the hypothalamus.
The mesolimbic reward system is typically stimulated by life-sustaining and pleasurable stimuli such as food, sex, alcohol, and drugs. The mesolimbic system is a complex interaction of multiple components of the brain including the cerebral cortex, locus ceruleus, nucleus accumbens, and the ventral tegmental area. This reward system is responsible for perception of both physical interaction with our environment and life-sustaining actions. Upon activation, the mesolimbic system releases neurotransmitters, primary of which is dopamine.