Opioid Agonists

      As well as killing pain, moderate doses of pure opioids produce a range of mild effects. They depress the activity of the nervous system, including such reflexes as coughing, breathing and heart rate. They also cause widening of the blood vessels, which gives a feeling of warmth and reduces bowel activity, which causes constipation.

Codeine is a narcotic, and this common opioid that has been administered for a long as we can remember. It is used for acute pain relief and could give a feeling of euphoria “a high” as well as a degree of sedation. With many prescription drugs, they carry some risk and they include side effects such as constipation and nausea and drowsiness (Canada, 2009) (Addiction.com, 2011).

The reason that this drug can be so intense and dangerous is because it falls into the category II narcotics. Many commonly known narcotics include opium, morphine, and heroin. The addiction rate of any of these drugs is phenomenal. Narcotics are central nervous system depressants that relieve pain without causing the loss of consciousness. They can also produce feelings drowsiness, mental confusion and euphoria. The analgesic effects of narcotics result from the drugs’ effects on the emotional aspects of pain. Many patients that experience intense pain say that after the administration of the narcotic, their pain is as intense as ever but no longer as bothersome. Because narcotics block the emotional side effects of pain they make it much more bearable.

Next, there is an extensive history of opioid use for pain management, and other symptom management as well. Morphine can be traced back to Civil War veterans trying to manage pain and, consequently, being addicted. “‘Drugs were already on the scene and being consumed at alarming rates long before the start of the war,’ said Mark A Quinoes, a scholar who studied drug abuse during the Civil War.” It was not until 1898 that heroin was on the market for commercial sale, considered a “wonder drug,” it began to spread in use along with users that found out injecting it would increase its effects. There was little known about these new opioids, they were even used as cough suppressants. Heroin worked for what is was being used as, a pain suppressant, and there were few other options. In 1914 the Harrison Narcotics Tax Act imposed a tax on importing and selling opium or coca leaves. In 1924 doctors were avoiding using opioids after being aware of their addictive nature which lead heroin becoming illegal. Without this opioid, doctors had to get creative when treating World War II soldiers, this sparked research into nerve blockers. These nerve blockers managed pain without the use of surgery. This was, unfortunately, not the end of the opioid. While these results were shocking the pharmaceutical industry still faces much leniency from the federal

Endogenous opioids work together to modulate pain by activating different types of opioid receptors (μ, δ, κ, ORL1). In contrast, most exogenous opioids are primarily using μ receptors to dampen pain. T exogenous opioids will disproportionately activate feelings of euphoria and breathing by activating every μ receptor in the brain/spinal cord to successfully diminish the sensations of pain. There is a relationship between this disproportionate activation and our problems of addiction, dependence, and overdosing.

The way opioids work is by attaching to one of three different type of neuronal receptors located in the brain and spinal cord (and possibly the peripheral nervous system). The three

Opioids are drugs taken for relieving pain. This drug has its effect on the human body through the reduction of the intensity of neuro-pain signals which are relayed to the brain (Opioids, 2009). Classic examples are the painkillers that include morphine, methadone, and hydrocodone among others. Pain is a physical suffering caused by illness or injury and may vary from steady to constant and throbbing to pulsating. It is not reasonable for anyone of us to except no pain except for those who suffer from anhydrases. This is an unusual genetic disorder that makes one unable to feel pain. Opioids play a significant role in the health system but they can be hazardous if used for pleasure or in a case of addiction. It is therefore important that

Methadone is a commonly used opioid to relieve pain in both veterinary and human medicine. To help develop appropriate pain management practices and to develop a quantitative model for predicting methadone dosimetry in plasma and specific tissues, a flow-limited multi-route physiologically based pharmacokinetic (PBPK) model for methadone in dogs constructed with Berkeley MadonnaTM was developed, specifically examining the Beagle and Greyhound breeds. The model accounts for intravenous (IV), subcutaneous (SC), and oral administrations, and compartmentalizes the body into components of venous blood, arterial blood, muscle, lung, brain, heart, liver, GI tract, kidney, and rest of body. This model was calibrated from plasma pharmacokinetic data

Opioids, which includes drugs such as morphine and codeine, bind to opioid receptors and help to relieve pain through the activation of K+ ATP channels. While these analgesic effects of opioids have been studied for decades, the rise of opioid tolerance and addiction creates a very interesting question: How did opioid tolerance and addiction evolve, and what are the ancestral reasons for these traits? To first understand this question, the evolutionary history of opioid receptors needs to be examined. Looking at the evolutionary history of the four opioid receptors seen today in Homo sapiens will help to understand how the functions of each receptor evolved. Secondly, following the evolution of the pathways involved with opioid receptor signaling and comparing that to other pathways would be helpful to understand if there are opioid-like receptor pathways in species besides vertebrates. Finally, looking at the evolution of the pathways involved with physical and social pain will be crucial to understanding why humans are vulnerable to addiction. Examining the effects of social interactions

Chemically related and interact with opioid receptors on nerve cells in the body and brain

The pharmacokinetics of opioids begins with the type of route of administration. The faster the opioid reaches the blood stream the quicker the effects of the opioid will reach the brain. Only about 50% of orally administered morphine passes through the blood brain barrier. Heroine is more lipid soluble than morphine therefore has an easier time of crossing the blood brain barrier. It is the fact that heroine has two acetyl groups attached to it that helps it be more lipid-soluble. This makes heroine 2 to 3 times more potent than morphine. Opioids bind to opioid receptors in the brain. There are 3 types of opioid receptors. There are Mu, Delta, and Kappa receptors. The Mu receptors are highly concentrated in the nucleus accumbens, the reward center of the brain, which explains why opioids are highly addictive. Opioids are eventually metabolized by the liver and

The test compound and agonist substances acetylcholine, carbachol, methacholine and histamine were obtained with enough volume to complete the experiment. A fresh guinea pig ilium obtained through a freshly killed guinea pig. An organ bath is needed with an attached water jacket and aerator to circulate the water. Sufficient amount of water is needed to circulate within the organ bath to keep it at a constant 37 ℃. Tyrode’s solution is required to immerse the tissue in. An isotonic lever attached to a transducer, which in turn connects to a chart recorder to measure the contractions of the guinea pig ilium is also needed for the experiment. Lastly, a cotton string to hold the suspended tissue is required.

The intravenous anaesthetic propofol is currently the least emetogenic general anaesthetic. These medications are thought to stimulate the chemoreceptor trigger zone (CTZ). This area is on the floor of the fourth ventricle and is effectively outside of the blood-brain barrier. This makes it incredibly sensitive to toxin and pharmacological stimulation. There are multiple neurotransmitters such as histamine, dopamine, serotonin, acetylcholine, and the more recently discovered neurokinin-1 (substance P) [2].

Opioids act by adhering to the opioid receptor proteins. The receptors are involved in the pain modulation process and occur in both the central and the peripheral nervous systems. In addition, the receptors bind endorphins or endogenous opioid peptides, which modulate pain in the body. Endogenous peptides are also involved in the modulation of mood and stress, as well as the reward and reinforcement mechanisms. In studies involving rats (Raghavendra, Rutkowski, & DeLeo, 2002), the activation of the opioid receptors with Morphine produces effects such as the sensitization of sensory nerves to the noxious stimuli.

Dr Redd, There are two basic ways pain medicines work. They either stop the pain signals from going to the brain or they alter the brain’s interpretation of the signals. Analgesics, such as acetaminophen, prevent the signals from reaching the brain. Narcotics, opioids from the poppy or narcotics synthesized by man, attach to protein opioid receptors in the brain or spinal cord to alter the perception or interpretation of signals to the brain. In the case of anesthetics, some increase Cl- in receptors to lessen the nerves ability to fire and others increase Na+ to reduce the action potential of the nerves.