The Nervous System

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The Nervous System essay assignment

The discussion in this chapter centers around the structure of the brain and how drugs affect the central nervous system (CNS). The chapter begins with a discussion of chemical signals in the brain such as hormones and neurotransmitters. The topic of receptors and their function at the synapse is covered in this section. The authors then discuss the structure of the brain paying close attention to those areas which are especially important for understanding drug effects in the CNS. These areas include the basal ganglia, limbic system and medial forebrain bundle. Also, discussions of the neurotransmitter pathways and the life cycle of a neurotransmitter are included. Neurotransmitters are chemicals released from neurons, and the glia is a very important brain cells that are a part of the blood brain barrier. The GABA is also a part of the neurotransmitter found in the brain. The chapter concludes by examining some of the modern techniques for brain imaging.

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Here are some of the different types of brain imaging technologies used at the BLA:

  • PET: Positron Emission Topography
  • MRI: Magnetic Resonance Imaging
  • fMRI: functional Magnetic Resonance Imaging
  • EEG: Electroencephalogram
  • CAT: Computerised Axial Tomograph

Each method has its own advantages and disadvantages and are appropriate in varying situations

Check out a site where you can look at brain imaging, google, and “brain imaging”. There are lots of choices, it’s pretty cool.

The desire to experience euphoria is one reason people use drugs. Although the notion of euphoria is influenced by one’s perception, drugs are used by some for this purpose. Others attempt to achieve euphoria naturally. Give some thought to the drawbacks and benefits of both drug-induced euphoria and natural euphoria.

Various parts of the brain are responsible for different types of behaviors and moods. In a utopian world, if we wanted to alter our behavior or mood, we could get a medically approved prescription to do so. We could get happy pills or pills to make us more assertive or pills to improve our memory (I wish). Actually, I don’t think this line of wishful thinking is too far, do you?

Since it has been demonstrated that certain drugs manifest specific behaviors in humans, we could conceivably alter one’s negative behaviors. We can tranquilize and sedate behavior. This reminds me of an old 1971 movie called “Clockwork Orange”; the setting is in the future and some young rebels get high, get into trouble and one of them ends up in jail and undergoes behavioral modification so he can be set free. If you get a chance, maybe you can stream it, as it shouldn’t be too hard to get. This whole idea, written by Anthony Burgess predicted a future where we alter criminals’ minds and modify their behavior with electro shock, drugs, and mental simulations. I wonder, is the future here?

A television commercial that appeared several years ago claimed that we can live better through chemistry, (I remember that commercial). With the advancements in science, our level of knowledge regarding the effects of drugs in the brain is increasing dramatically. Is it possible that we have not learned how to harness the information we have discovered? Some examples of technological advances may be disadvantageous or harmful in the long run, such an example is our modern invention of birth control pills.

A relatively new phenomenon is the development of “designer” drugs, which are molecular derivatives of existing drugs. Since the action of many existing drugs is not completely known, it is impossible to know what the effects of these designer drugs will be. There can be very detrimental consequences from designer drugs, so we will explore this issue further.

Also, it seems that there are going to always be people, and I hope it’s not the majority, that do not look at labels or follow the prescription as prescribed. Many people blindly follow doctors and nurses’ orders and yes, you should be going to medical care that you trust and believe in, but it never hurts to read the labels and reasons to take them for yourselves. Be proactive in your own health and welfare, which would also mean diet and exercise, drink plenty of water and do not take anything that is not prescribed to you. Many Americans seem to be uninformed about prescription addiction and my biggest concern is the elderly. Yet still, in the past the most popular abuser of prescription drugs was the white, upper/middle class. Today things are changing and this type of abuser is now younger and crossing class lines. The percentage of current prescription abusers today have significantly increased from those aged 12-17 years of age and from 2.2% in 2013 to 2.6% in 2014 and rising. (SAMHSA).

The Food and Drug Administration (FDA) is in charge of implementing the guidelines that our drug companies have to abide by and this includes labeling with the correct effects, and possible effects. The FDA also ask all consumers to report any negative effects that they may have from the drug to them or their physician.

For the fun of it, check out the Society for Neuroscience (Links to an external site.) website.

The Actions of Drugs

This chapter is an introduction to the field of pharmacology. The chapter begins with a discussion of the source of psychoactive drugs. The authors’ explain that almost all drugs are derived from plants. The chapter continues by introducing types of drug names and drug classifications schemes. Prescription labels are very important to read and consider; however, before you go off in a whole other direction after you google a prescription drug your doctor wants you to take, be prepared to discuss with your doctor as well. Not all side effects are true for everyone and the benefits of taking the drug may far outweigh the consequences of not taking it at all. Every drug has a side effect. The following sections examine several topics relating to drug effects and include discussions of placebo effects, drug potency, routes of administration and the blood/brain barrier. The chapter concludes with a discussion of the three types of drug tolerance.

Generic drugs and brand name drugs can be called by their chemical, generic or brand names. Generic names specify chemicals and are used in public domain. Brand names are assigned by manufacturer of a generic produce and the use of brand names is restricted to the original copyright holder. After a seventeen year period other companies can produce the drug under a generic name.

Drug classifications, observations and detection: Drugs tend to be categorized by their effects on the user and are identified by using the Physician’s Desk Reference. Drugs can be detected in body fluids with some degree of accuracy. Nonspecific factors in effects of drugs is that it is possible to detect without chemical activity. Even the background and perception of the individual can produce an effect. Double-blind studies are used in research of effects of drugs and placebos to reduce pain may actually work as a result of production of endorphins. This tells me that if we found other ways to release endorphins naturally we could find ways of healing that are not only cost effective, but were also much less intrusive to our CNS.

Specific effects of drugs are influenced by dose levels. Safety margins of a drug are the difference between its effective dose and a lethal dose. Reminding us that there is indeed a threshold beyond which drugs have no additional effect. As the old saying goes, “you can only get so high” and likewise, there is only so much pain medication a patient can be given before respiratory failure or heart failure happens.

The potency is the ability of a certain amount of drug to obtain a particular response and to determine its most effective dosage. Time-dependent drugs operate according to the rate of absorption and the rate of deactivation. Still some drugs can act in an additive mode- for instance, combining depressants like alcohol and Valium.

Once drugs are ingested into the system and hit the bloodstream from the gastrointestinal tract then it must pass through cell membranes. If injected intravenously the drugs will enter the circulatory system extremely quickly. As you can imagine, intramuscular and subcutaneous injections do not operate as quickly as straight into the vein. The circulatory system is the most important system in transporting drugs to the brain.

A huge concern of course when using intravenously is AIDS, here are the latest statistics I could find.

  • In 2016, 36.7 million people were living with HIV.
  • In 2017, about 20.9 million people living with HIV were accessing antiretroviral therapy, up from 17.1 million in 2015 and 7.7 million in 2010.
  • In 2016, 1.8 million people became newly infected with HIV. This represents a decline in annual new infections of 16% since 2010, a pace far too slow to reach the United Nations’ Fast-Track Target of fewer than 500,000 new infections per year by 2020.
  • Since the beginning of the pandemic, 76.1 million people have contracted HIV and 35 million have died of AIDS-related illnesses.
  • Annual deaths from AIDS-related causes have declined 48% over the past 10 years, from 1.9 million in 2005 to 1.0 million in 2016.
  • Since the beginning of the pandemic, more than 17 million children have lost one or both parents to AIDS.

Thankfully, AIDS death rates have declined 48%, from 1.9 million in 2005 to 1 million in 2016. But there is still much work to be done and the best cure is not using or sharing needles for drugs. This has been such a tragic plague on our worldwide citizens, Africa having been the hardest hit and AIDS place of origin. We need to still be vigilant and continue to work to bring these statistics down much further.

Drugs can also be inhaled to produce effects quickly because the capillary walls are very accessible in the lungs and drug enters the blood easily. They can also be applied topically to the skin and through suppositories, which is great when a person cannot keep anything down! Drug effects are influenced by protein molecules in the blood as well as by the blood-brain barrier.

(This was a submission from a past student that is a Registered Nurse; I thought her comments were noteworthy for this lesson.)

The synergistic effect of recreational drugs often mask one another. Frequently the individuals using recreational drugs are most interested in their high, and often don’t take the time to educate themselves on the potential side effects or compounding side effects. In addition, if you take something as common as over the counter medications, such as aspirin, acetaminophen, and ibuprofen… very few individuals even know the difference between these medications let alone their interactions. For example, when people have fevers, they often take aspirin and Motrin/ibuprofen together. While acetaminophen would be the most appropriate medication to take for fever, the general population does need to know that aspirin and ibuprofen both thin your blood, and when taken together, enhance the anticoagulating properties of one another.

Tolerance occurs when repeated administration of the same dose of a drug produces gradual diminishing effects. It can occur with any drug, stimulants and depressants. Such is the case with alcoholics showing behavioral tolerance as well. Drug disposition tolerance is the process whereby a drug is deactivated and/or excreted more rapidly when administered repeatedly.

This brings us to the withdrawal symptoms of this type of tolerance. Depending on the drug, the dose, the length of time a person has been using the drug, how much they weigh, age, personal tolerance, diet, many factors are involved. However, some commonalities include irritability, jitters, sweats, loss of appetite, loss of weight or weight gain, confusion, unreasonable fears and hallucinations. Some or all of these could occur. Later in the class we will be discussing steroids, the use, abuse and withdrawal symptoms of this drug. Sometimes for good reasons, sometimes not. Your text does have a box you can read regarding “Avoiding Withdrawal Symptoms”, of course it is suggested to take less of the drug, just under what controls all pain. Let the patient feel a bit of pain as they are healing, that way they will know what they can and can’t do. Say it was a badly broken leg and had surgery, after a few days of complete pain control they start backing off from the dose a bit at a time. The patient may feel some discomfort, but will know that they cannot put all their weight on the leg or do things that might re-injure the leg. When a person is too heavily medicated and does not feel a thing, it can also be dangerous. As someone once said, “pain helps us know we’re alive”. As I always say, “but I don’t want to be in pain.” We must find that right balance while healing.

One last topic that I wish to bring out is the “grapefruit juice effect”. If your edition does not have the information in it then look it up on the internet. I feel this is important information for a couple of reasons, the most being that we see how something so innocent can cause a drug interaction that could be harmful. The second, because it’s such a common food that we need to know this, if not for ourselves, for someone we love may like grapefruit juice while taking some kinds of drugs, like calcium-channel blockers for blood pressure. Please look it up and answer the question in your lesson.

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