Tagged: hypothalamus

Study Drugs: Pills to Supercharge The Brain?

studying-boh

We have officially reached 1500 views! Thank you to everyone who has taken the time to read this blog so far. Truly appreciate the support.

This week’s question comes from Joe, who asks “I’ve heard of certain medications, like Adderall and Provigil, that give people a tremendous boost in focus and work ability. Provigil is especially becoming popular with the Wall Street types. How do these drugs work and are there any major negative side effects?”

I think most people have heard of stimulants becoming popular with the big city finance types, starting with cocaine in the 80’s and moving to more sophisticated pharmaceuticals like these as the years progressed. More recently, these types of drugs have become popular with otherwise normal college and even high school students looking to get more done in less time. The military has been using pills like this to keep pilots and other essential personnel awake for days at a time since the early 20th century.

Before we start, one comment: contrary to what some people may believe, no pills as of yet actually make you “smarter” or otherwise enhance your pre-existing function. What they actually do is alter your perception of reality, directly in the brain and/or by systemically suppressing signals of fatigue. The same ability is present no matter what you take, just the drugs can temporarily ease the natural feelings of fatigue that would ordinarily hold back full function.

So to answer the question generally, we can split the drugs into two basic categories. The first category, which most people are familiar with, are stimulants. Stimulants are defined as any chemical that temporarily increases physiological function. Obviously this is a very wide definition that can apply to a wide variety of things. Some drugs we encounter every day are weaker stimulants, like nicotine, than others, like caffeine. Many stimulants are illegal, like cocaine and methamphetamine. Stimulants can and often do cause addiction. Likely the strongest widely available class of stimulants are amphetamines. Adderall is actually a mix of two different types of amphetamine salts, amphetamine and dextroamphetamine. Lets explore how amphetamines work in more detail.

Amphetamines function by causing a large rise in the levels of dopamine and norepinephrine in the brain and prevent their reuptake, allowing these chemicals to continue to exert influence longer than normal. The specifics of this action are not important to this discussion but are described very well in this article. We have already talked about the function of norepinephrine in the brain (here), so I won’t repeat myself. Take a peek at that other article if you need a refresher.

The changes in dopamine are also tremendously important. Dopamine is a neurotransmitter in the brain responsible for a wide variety of functions. One major function is control/ heavy influence over the reward and alertness centers of the brain. So when a substance causes a major release of dopamine, one effect is you feel really good, have a very positive mood, and are very alert. MDMA, the active ingredient in the drug ecstasy, exerts its influence largely by this mechanism (it also happens to be an amphetamine). This is also where amphetamines give us the ability to remain awake. High levels of dopamine can also have an impact on higher level brain functions such as motor control, causing abnormally high motor activity and low threshold for movement. This is possibly the source of the “jitters” people get when they take dopamine releasing drugs like amphetamines. It is also the reason movement is so difficult with Parkinson’s Disease, as the dopamine producing center of the brain is damaged and dopamine levels are lower than normal.

As you might imagine, amphetamines are incredibly addictive due largely to their reward center influencing mechanism of action. They also have negative side effects such as appetite suppression that can cause longer term health effects if left unchecked. As such, their use should be limited only to those instances where their value outweighs the cost.

The second category of drugs are non-stimulants. These are drugs that seek to mimic the individual effects of the stimulant drugs without similar side effects, including addiction potential. For the treatment of ADHD, sometimes SNRIs (selection norepinephrine reputake inhibitors) are used as an alternative method to amphetamines. This seeks to produce the increase in norepinephrine found in amphetamine medication without the associated addiction potential from dopamine-related activity.

The drug you mentioned, Provigil, attempts to do a similar thing by influencing dopamine levels without a massive increase all at once. By upticking the dopamine transporters in the brain, the levels are increased more gradually and causes the desired alertness without the dose of euphoria that underlies the addictive nature of amphetamines and other stimulants. Mind you, amphetamines do a similar thing, but they also cause a massive release and prevent reuptake so it is likely that transporter alteration is the least negative of the three effects. It also has an impact on norepinephrine, serotonin, and histamine levels in various areas of the brain through its impact on neurons in the hypothalamus, though this effect is much less well understood. However, unlike amphetamines, it seems to have some potential for real cognitive enhancement. There have been basic studies that show some value to this end, and as such this drugs and future drugs like it may actually start to approach a “brain pill” rather than simply tricking your body into not being fatigued.

On the face of it, Provigil seems to work for its intended purpose and is well tolerated, however its full mechanism of action is not well understood. Based on its known mechanism of action, it is likely much less addictive than amphetamines and other stimulants. However, because it is also much less well understood it is something that should also be treated with caution and used only as indicated/prescribed.

In sum, these different types of drugs often work as marketed, but each has their own positives and negatives. You should only use these drugs under the regular care of a physician who prescribes them to you for a legitimate condition. But, should you decide to obtain them outside of that, I would advise you tread carefully. While they may seem innocent at the time and certainly useful in many contexts, you may be making a deal with the devil in the process. There are much more beneficial methods of increasing alertness (exercise, meditation, etc.) than taking a potentially dangerous pill. I would suggest trying those before jumping to a pharmaceutical solution.

Hope this helps, Joe! Thank you for the question. As always, feel free to submit questions to me directly at the link above.

Till next time, tread lightly.

Justin

Sources:

http://www.sciencedirect.com.libproxy.usc.edu/science/article/pii/S0301008205000432

http://psycnet.apa.org.libproxy.usc.edu/index.cfm?fa=search.displayrecord&uid=1998-10330-005

http://journals.lww.com.libproxy.usc.edu/jonmd/Citation/1961/12000/Amphetamine_Addiction.3.aspx

http://pharmrev.aspetjournals.org.libproxy.usc.edu/content/14/1/1.short

http://www.cnsforum.com/imagebank/item/Drug_amphet_high/default.aspx

http://europepmc.org.libproxy.usc.edu/abstract/MED/10505821

http://psycnet.apa.org.libproxy.usc.edu/index.cfm?fa=search.displayrecord&uid=2004-14364-011

http://www-ncbi-nlm-nih-gov.libproxy.usc.edu/pubmed/0007701191

http://www.sciencedirect.com.libproxy.usc.edu/science/article/pii/0278584688900140

http://www.medscape.org/viewarticle/739491

http://www.pnas.org/content/102/9/3495

http://www.ncbi.nlm.nih.gov/pubmed/7751968

http://www.ncbi.nlm.nih.gov/pubmed/16497598

Stressed Out: The Impact of Stress on the Immune System

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Hello readers! Sorry for the delayed post, been a hectic last few days getting my life arranged for my jaw surgery on Friday. This week’s question comes to Desiree, who asks “I’ve noticed I get sick more often when I’m really stressed about school. What exactly is happening that causes this and how can I avoid it in the future?” Well Desiree, I think most of us have experienced this phenomenon at one point or another. For some people, it can cause nastier problems than just more frequent colds. But, you’re spot on in your assessment that stress plays tricks on the immune system. Before we get to your question, we should first explore the relevant physiology of stress.

This response, commonly referred to as “fight or flight,” is meant to save your life in the event of an imminent threat or direct attack. It involves many different body systems and is a truly systemic in its effect. The complex interconnectedness is beyond the scope of this article, but the following is the basic rundown. I highly encourage independent research of this topic for a more complete picture.

The stress response is generated in the brain based on sensory input (ie. you see something scary coming towards you). The relevant signals are collected, processed, and travel to one or both of two locations. One is the locus coeruleus, which is responsible largely for initiating the stress response via production of norepinephrine in the brain. The other is the collective Raphe nuclei, which are responsible for, among other things, anxiety and are major serotonin producers in the brain. The subsequent release of neurotransmitters from one or both of these areas of the brain produce the stress response cascade throughout the rest of the body.

The signal produced by the brain has two major parts. First, direct neurological stimulation of the adrenal glands produces adrenaline very quickly. Second, the neurological signal initiated in the locus coeruleus is translated into hormonal signal by the hypothalamus. This then affects the pituitary gland and causes the release of ACTH, or adrenocorticotropic releasing hormone. This hormone enters the blood stream and stimulates the production and release of cortisol into the blood. Together with norepinephrine, which is also released by the adrenal glands along with adrenaline, these molecules are the dominant effectors of the stress response across the body. These molecules also feedback with the brain structures that originate them, creating a very complex web of effects that are not yet fully understood (ex. cortisol has an effect on serotonin production in the Raphe nuclei).

Adrenaline and norepinephrine (collectively a part of a group of molecules known as catecholamines) affect the sympathetic nervous system. It is not important to know what this is for the purposes of this discussion, just know it as one half of the body’s automatic systems. These molecules have a number of functions, namely opening the air passages, altering blood flow throughout the body, slowing digestion, and increasing heart rate. Many of the immediate physical effects you feel during a stressful situation are due to these because their release is much quicker than cortisol. This is also why adrenaline is used during anaphylaxis (allergic reaction), as it can open the narrowed airways and control the potentially deadly swelling.

Cortisol’s role is much different. Like the catecholamines, its job is to keep you alive when fighting for your life, but by a vastly different mechanism. Instead of priming the body to fight or move, cortisol’s main function is to augment its ability to produce and release glucose into the blood stream. It does this by both encouraging the breakdown of more complex storage sugars as well as increasing the processes that convert other molecules, such as proteins and fats, into glucose (known as gluconeogenesis). In other words, it provides the fuel you need to do whatever is necessary to survive, via the slash and burn method if necessary. It also has some inhibitory effects on body systems unnecessary in the short term, such as bone formation. Unfortunately, another one of cortisol’s inhibitory effects makes it the focus of this discussion for the remainder: immune system depression.

While it may seem counterintuitive to curtail the immune system when stressed, the reason for this is fairly simple once we understand the different nature of stress responses. The body has two basic types of stress: acute and chronic. Acute stress, caused by immediate stressors like being attacked or frightened, causes the release all of these molecules in tolerable amounts that temporarily empower us without a tremendous long term downside. Suppressing immune function in acute stress is smart because it holds off inflammation. As anyone who has injured themselves under stress can attest, function can be maintained through the injury until the stressful situation resolves. If the immune system were not held at bay during that time, the injury would quickly become immobile and hinder survival efforts.

However, chronic stress, with which many in graduate school or in dangerous/busy professions are intimately familiar, tips this balance towards the negative. If cortisol levels remain elevated continuously, the effects on the body due to continued suppression can cause a myriad of problems, including more frequent infections.

The immune suppressing function of cortisol has been utilized in medications for decades. Steroids (not the work out kind) such as prednisone and dexamethasone are commonly used in medicine to reduce inflammation, swelling, and the negative effects of autoimmune diseases. However, long term use of these drugs can have similar side effects as chronic stress. Thus, just as long term steroid use is often avoided due to its negative effects on the body, so too should chronic stress be avoided to prevent the same.

Unfortunately, cortisol is a natural part of the body and to attack it pharmacologically could be disastrous. So, stress management techniques are key to controlling its release by controlling the stimuli presented to the brain. Exercising, meditation, massage, acupuncture  and other similar activities have been shown clinically to be beneficial for stress reduction. Given that they have minimal downside and often benefit quality of life, they are also the most advisable methods of stress control. If these prove ineffective, low doses of anti-depressant medications that affect the serotonin and/or norepinephrine in the brain may be helpful for this purpose (as it already is shown to be for people with severe anxiety).

Hope this helps, Desiree! Thank you for the question. As always, I encourage question submission via the link at the top of the page!

Till next time, que le vaya con Dios.

J

Sources:

David DJ, et al. “Neurogenesis-Dependent and -Independent Effects of Fluoxetine in an Animal Model of Anxiety/Depression.” Neuron. 62(4); 2009 May: 453-455.

Laaris L, et al. “Stress-induced alterations of somatodendritic 5-HT1A autoreceptor sensitivity in the rat dorsal raphe nucleus — in vitro electrophysiological evidence.” Fundamental and Clinical Pharmacology. 11(3): 1997 May: 206–214.

Tsigos C, et al. “Hypothalamic–pituitary–adrenal axis, neuroendocrine factors and stress.” Journal of Psychosomatic Research. 53; 2002: 865 – 871.

Valentino RJ, et al. “The Locus Coeruleus as a Site for Integrating Corticotropin-Releasing Factor and Noradrenergic Mediation of Stress Responses.” Annals of the New York Academy of Sciences. 697; 1993 Oct: 173-188.

Welch WJ, et al. “Mammalian stress response: cell physiology, structure/function of stress proteins, and implications for medicine and disease.” Physiology Review. 72(4); 1992 Oct: 1063-1081.

http://learn.genetics.utah.edu/content/begin/cells/fight_flight/

http://waterhouselab.com/?page_id=302

http://cmhc.utexas.edu/stressrecess/index.html

http://www.mayoclinic.com/health/stress/SR00001

http://dujs.dartmouth.edu/fall-2010/the-physiology-of-stress-cortisol-and-the-hypothalamic-pituitary-adrenal-axis#.Ua17HGTwLIg