Brief History of Opiates, Opioid Peptides, and Opioid Receptors - Report Example

Opiates Opiates are alkaloid derivatives from the Oriental poppy, Papaver somniferum, and have been in use for centuries by physicians all over the world, for treating various diseases and for alleviating pain. “Opiate is a term generally used to designate drugs derived from opium and their chemically related derivatives, such as semi synthetic alkaloids” (United Nations, 2009, 78). Naturally obtained opiates include morphine, thebaine, papaverine, and codeine; while the synthetic ones constitute of oxycodon, hydrocodone, and the most famous synthetic opiate is known as heroin. Opiates, which are used primarily as medicines, depress the Central Nervous System, thus alleviating pain. However, if misused/ abused, opiates produce drug dependency, addiction, increase in the tolerance levels, and severe withdrawal symptoms. The opiates (chiefly heroin), in majority of the countries are considered to be banned drugs, owing to their capacity to produce drug dependency. My article will take a close look at these opiate drugs, and will explore the subject to study the history, pharmacology, how these drugs are taken, the ingredient (make up), legal aspect of people addicted to opiates, and the treatment methods available for the opium addicts. History of opiates: “Presently she cast a drug into the wine of which they drank to lull all pain and anger and bring forgetfulness of every sorrow". This quotation cited from The Odyssey, written by Homer in ninth century BC, shows us very clearly that the potent use of opiate drugs was known right from ancient times. Archaeologists have shown the presence of Papaver somniferum from Neolithic period excavations in Switzerland that date back to around 3200BC (Merlin, 1984). Amongst scholars “there is a general agreement that the Sumerians, who inhabited what is today Iraq, cultivated poppies and isolated opium from their seed capsules at the end of the third millennium BC” (Brownstein, 1993, 5391). It is speculated that it was from this ancient land of Sumeria, opium spread to various parts of the world, via the various trading routes (land and sea) that were followed by the merchants of the ancient civilizations. The English word ‘poppy’ is a Latin derivative, and means ‘sleep inducing’. At the beginning, opium was used mainly in religious rituals, to cure diseases like diarrhea, to lessen pain, and also to create an effect of transcendental euphoria. It was in the eight century that opium was first brought to China and India (both the countries are the leading modern day exporter of opiates) by Arab traders, and it was from here that it spread to Europe. There was widespread use of opium as a medical substance during the sixteenth century Europe. This is evident when Thomas Sydenham, a sixteenth century English physician who was the first to produce the opiate preparation known as ‘laudanum’, comments “among the remedies which it has pleased Almighty God to give to man to relieve his sufferings, none is so universal and so efficacious as opium” (cited in Goldberg, 2009, 7). Opium trade had always been a lucrative source of income, and history has seen two Opium Wars; one in 1839-1842, and the second one in 1856, between England and China, in a bid to gain supremacy over the opium trade and cultivation. Opium has always been used and traded quite openly, and it was only in the late twentieth century that a ban was applied on opium after the infamous drug wars. However heroin, a semi synthetic derivative of opium, first produced by C.R.A. Wright, a British pharmacologist in 1874, and marketed by Bayer 21years later, was dealt with great wariness right from the time of its conception, and was banned as early as 1926 in US, owing to its highly addictive nature. Structure of opiate drugs: Opiates are a part of the biosynthetic group of alkaloids, knows as benzylisoquinoline. Naturally occurring opiates like the morphine and codeine have a complex structure that is difficult to synthesize, thus are obtained only by extraction from the poppy plants. Morphine which is the most prevalent amongst all other opiate drugs can cause pulmonary edema, cardiac/ respiratory failure, respiratory depression, coma, if given at a dosage of 120-250 mg, equivalent to about 2 grams of pure opium. The most common semi synthetic drug is heroin (diacetylmorphine), which is produced when acetic anhydride reacts with morphine. Other semi synthetic drugs like hydromorphine (‘dialudid’, a popular prescription drug with a potential for high abuse) and oxymorphone (not very common but has a higher potency, thus more addictive) have structure similar like that of morphine. (A) (B) (C) (D) Fig 1: (A) shows the basic chemical structure of the benzylisoquinoline alkaloids. The opiate drugs are all modifications of this basic structure; (B) Chemical structure of morphine; (C) Chemical structure of heroin; (D) Chemical structure of codeine (Source: Zenk, et al., 1985, 725-738.) Pharmacology of the drug: Opiates work in our body via receptors, where they bind with the receptors cells and prevent them from receiving the second messenger cells. Opiates have been known to inhibit the adenyl cyclase that closes the calcium channels and in turn opens the potassium ones. By inhibiting the adenyl cyclase, the pain signals are prevented from being transmitted, thus making opiates an effective pain killer. Opiates are of two kinds, agonist and antagonist. Agonists (opiates with n-methyl group), bind to the receptors and that cause specific conformation changes, that in turn prevent the entry of the signals from the second messenger. Antagonists (opiates with N-allyl or N-cyclopropyl groups) do not show any conformation changes, and serve to inhibit the agonists. There is another kind of opiate drug, which is a mixed Agonists and Antagonists type, with a structure similar to that of the Antagonists, and these are the less addictive varieties. The chief opiate drug receptors are the Mu, Delta, and Kappa. The Mu subtype is the most important in regards to analgesia. Mu receptor specific agonists produce the analgesic effect, while the kappa specific agonists are known to produce dysphoria, psychomimetic effects, while also producing disorientating effects. Human bodies produce enkephalins, which are endogenous peptides (like morphine), and these are located at the brain and spinal cord. They function in close association with opiate receptors to inhibit the production of substance P in the spinal cord, which relieves pain. It is this supra spinal effect of the drug opiate, that helps in pain alleviation. Legally, opiates are administered as medicines, mostly to provide relief from pain in terminal patients, in the form of injections via the subcutaneous, intramuscular, or intravenous channels. Illegally, opiate drugs can be snorted, inhaled or even injected (commonly known in the addict circles as ‘shooting up’ or ‘slamming’). Legal aspect of people addicted to opiates: Almost in all countries worldwide, opiate drugs, especially heroin, are considered to be illegal substances, and are therefore banned under the Controlled Substances Act as Schedule I and IV. Except for government sponsored research works pertaining to medical studies and other scientific works, it is illegal to use opiate drugs. Thus it is illegal to take, inhale, sell or buy, or even possess opiate drugs without any proper authorization. Most countries use the control of licensing system to safeguard legislations made against the illegal use of opiate drugs; and under this law it is criminal offense to produce, consume, trade or even possess opium and its derivatives. Such laws are mainly to safeguard the general civic and moral health of a country’s population. However a person addicted to opiate drugs may commit felony and other serious crimes, in order to maintain a steady supply of these extremely addictive drugs, thus becoming liable for double legal penalty. There are not many laws that directly affect a substance user, or help in decreasing the number of drug addicts. Most laws are created in order to tackle people who trade in illegal opiate drugs, and these people are generally part of a large syndicate of organized crime, making it extremely difficult for the law enforcement agencies to pin them down. The illegal nature of these drugs combined with the urgency with which the addicts crave for them, make them extremely expensive; often pushing such substance abusers into a life of crime. Treatment for opiate drug abusers: This involves administrations of both medications and behavioral therapies, and starts with detoxification of the body and cleaning the body of all traces of opiate drugs. Withdrawal symptoms are controlled by administering Clonidine and buprenorphine, while to prevent the victim from relapsing into drug abuse, medicines like Naltrexone, Methadone and Buprenorphine are administered. Group and individual counseling sessions; teaching how to manage regular stress through the applications of various cognitive-behavioral skills; contingency management programs with the drug abuse patient; all these constitute the various behavioral therapies. However, the best way is to create awareness, especially amongst the teenager groups, so that they avoid abusing the opiate drugs, instead of going for the various rehabilitation programs to be treated after becoming an addict. Nothing beats the age old adage which very wisely says “prevention is better than cure”. References Brownstein, M. (June 1993). A brief history of opiates, opioid peptides, and opioid receptors. Proc. Natl. Acad. Sci. USA. Vol. 90, pp. 5391-5393. Goldberg, R. (2009). Drugs across the Spectrum. California: Cengage Learning, 7. Merlin, M. (1984). On the trail of the ancient opium poppy. London: Associated University Presses. United Nations. (2009). Narcotic Drugs: Estimated World Requirements for 2009 (Statistics for 2007). United Nations Publications, 78. Zenk, M., Rueffer, M., Amann, M., and Deus-Neumann, B. (1985). Benzylisoquinoline Biosynthesis by Cultivated Plant Cells and Isolated Enzymes. Journal of Natural Products, Vol. 48, No. 5, pp. 725-738. Retrieved at, http://epub.ub.uni-muenchen.de/3630/1/010.pdf Read More