Opiates on the Brain

By Jennifer Hagaman

        Opium is formed from preparation of the opium poppy which can be collected from gummy fluid that oozes out of a cut in the    developing seed pod of a poppy.  The sap is then dried into a ball, or dried into powder, or it can be made into an alcohol water extract.  Opiates can be injected, smoked, taken orally as pills, or snorted.
 Why we use opiates is a question of how much pain one is in.  That is, humans have been using opiates such as morphine and heroin for  thousands of years to lessen pain and for euphoria.


     The effects of opiates are many, including a rush immediately after injection, extreme relaxation, decreased sensation of pain, and decreased sexual drive.  Sexual drive is decreased as the opiate affects the release of hormones and transmitters that regulate sexual behavior.  Opiates also effect other areas of the body including the pupils of the eyes.  That is, they cause extreme constricting.  Other effects include nausea and vomiting along with slowed breathing.   The brain is stimulated and thus causes nausea and vomiting usually occurs to detoxify the system.  Moreover, opiates also increase muscle tension in the gastrointestinal tract.
    The way that opiates work on the brain is that they bind to specific receptors , that is, the neurotransmitters in the brain that control movement, moods, and physiology, which includes digestion, body temperature and breathing.  They cause the neurotransmitters to fire at a high rate as they would in times of extreme stress.
Another effect of opiates is that they have a damaging side effect known as addiction.  This addiction that one may have to opiates is one of the hardest to overcome.

    An important discovery of proteins called opiate receptors in the brain shows how opiates affect the body and established an important new method for studying drugs.  Through this, a discovery of opiate like chemicals produced in the body that control pain, immune responses and other body functions was established.  The opiate receptor was discovered in 1973 and since this discovery, scientists have been able to establish the basic technique for studying brain receptors still used today.  
The opiate receptor and other brain receptors are proteins located on the surfaces of nerve cells, or neurons.  The brain works through neurons communicating with each other by releasing signaling chemicals called neurotransmitters.  These chemicals attach to the receptors on nearby neurons much like a hand fits in a glove.  
    What is exciting about the discovery of the opiate receptor discovery is that prior to 1973, scientists knew little about opiate drugs and how they affected the brain.  They knew that opiates acted on specific neurons, and that opiate drugs that blocked their action all had a similar molecular structure.  Although they suggested that opiates worked by attaching to a receptor, few receptor molecules had been found.  Since the opiate receptor is only a small percentage of the brain tissue, it was initially hard to find.  The way it was found was by using radioactive naloxone, which  is a synthetic opiate with a strong attraction to the opiate receptor.  This discovery of the opiate receptor was important because it suggested that opiate drugs work by mimicking the natural opiate like molecules used and made in the brain.  With this came the identification of endorphins which have the same actions as say, morphine.
    Scientists can map brain structures that contain opiate receptors that are responsible for opiate drug effects on the body and researchers believe that opioid receptors may be important for the release of luteinizing hormone which is an important reproductive peptide.  Opioid receptors are also important for regulation of the immune system.   

           Although a person might have a positive reaction to an opiate, addiction usually doesn't happen the first time they use a drug.  Opiates are considered extremely addictive and this addiction can affect the structure and function of the brain.  Opiates can alter the brain and affect one's motivation and emotions.  The brain changes over time and hence a person's behavior changes.  Moreover, if one uses a high enough dose of drugs, frequently enough,  and over a long period of time, the drugs can change the way the brain works.  The way in which the nerve cells communicate are changed so a compulsive, out of control use develops despite experiencing some of the many side effects.   More specific effects of opiates on the brain include changes in the synapses and shapes of brain cells.  Chronic use is linked with structural changes in the size and shape of specific neurons.  That is to say that there is a difference noticed in the brain between a chronic opiate user and an occasional user.

          A very popular opiate used in treating pain today is hydrocodone, also known as vicodin.  Hydrocodone that is combined with acetaminophen is known as vicodin.   Use of this drug has been increasing over the past decade as an estimated 7 million dosage units were diverted by the DEA in 1994 and in 1997 over 11 million.  Over 56 million new prescriptions were written for hydrocodone products and by 2000 over 89 million were written.  The average consumption nationwide has increased 300% from 1990 on.  There has been a 500% increase in the number of Emergency Department visits that are contributed to hydrocodone abuse.  In 2000, the estimated visits were 19,221.  The DEA laboratory system seized and analyzed over 1.3  million hydrocodone tablets in 1997.  
    Since hydrocodone is considered to be morphine like in every aspect, it is easy to see why one may choose to use and abuse this substance.  It is easy to get by prescription and it is perceived to be safe, but it is highly addictive and one may even develop a tolerance to the drug, thus promoting a higher dosage needed to achieve the desired effect.