China
Africa
Explore chapters and articles related to this topic
Screening and Pharmacological Management of Neuropathic Pain
Published in Suvardhan Kanchi, Rajasekhar Chokkareddy, Mashallah Rezakazemi, Smart Nanodevices for Point-of-Care Applications, 2022
Manu Sharma, Ranju Soni, Kakarla Raghava Reddy, Veera Sadhu, Raghavendra V. Kulkarni
During intense or persistent pain, neurons in the dorsal horn liberate endogenous opioid peptides (beta-endorphin, enkephalins, dynorphins) to diminish the perception of pain. These endogenous opioids modulate pain-related signals by inhibiting the transmission of signals at synapses. Opioid receptors (µ, κ, and δ) are present in different areas of the brain, brain stem, spinal cord, and peripheral nervous system. Opioids exhibit mood-elevating properties because of specific affinity towards µ receptors in the brain whereas they enhance the performance of cells in the brain stem involved in inhibition of descending pain. Opioids also inhibit the transmission of nociceptive pain signals at the spinal cord and peripheral nervous system. Agonistic binding of opioids to all receptors elicits the closure of Ca+2 channels which diminishes neurotransmitter release and inhibits postsynaptic neurons [35–37].
Control of Postoperative Pain by Self-Administered Opioids
Published in Robert B. Northrop, Endogenous and Exogenous Regulation and Control of Physiological Systems, 2020
With the wide and specific distribution of endogenous opioids in the CNS and peripheral nervous system comes the necessary fact that there must also be a multiplicity of opioid receptors on these nerves. In the CNS there is evidence for at least four major types of opioid receptors, classified as μ, κ, δ, and σ. Undoubtedly, there are subclasses of these four classes. μ and κ receptors are associated with analgesia; however, not all receptors are associated with analgesia. Dysphoria and psychomimetic effects are associated with σ receptors in the limbic system of the CNS, and δ receptors may be involved with affective behavior.61 The situation is made more complex because of cross-talk between exogenous opioids caused by nonunique affinities to a given class of receptor. This crosstalk is illustrated by the fact that certain exogenous opioids can have agonist (Ag), partial agonist (pAg), or antagonist (Ant) action at certain receptor types. Table 9.1, adapted from Goodman and Gilman,61 illustrates some of these properties. Note that naloxone is the treatment of choice for opioid poisoning (as with morphine or heroin); it has no direct respiratory depressant action.
Homo Sapiens (“Us”): Strengths and Weaknesses
Published in Michael Hehenberger, Zhi Xia, Our Animal Connection, 2019
Another important category of pain medicines are the opioids. They are limited to the natural alkaloids found in the resin of the opium poppy although some include semi-synthetic derivatives. An important semi-synthetic opioid that is synthesized from codeine, one of the opioid alkaloids found in the opium poppy, is hydrocodone. It is a narcotic analgesic used orally for relief of moderate to severe pain, but also commonly taken in liquid form as an antitussive/cough suppressant. Opioids act by binding to opioid receptors. They are found principally in the central and peripheral nervous system and the gastrointestinal tract. Opioid receptors mediate both the psychoactive and the somatic (associated with voluntary movements of the body) effects of opioids. Medically, they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, suppressing cough, and suppressing opioid induced constipation. However, opioids are also frequently used nonmedically for their euphoric effects or to prevent withdrawal. Side effects of opioids may include itchiness, sedation, nausea, respiratory depression, constipation, and euphoria. Tolerance and dependence will develop with continuous use, requiring increasing doses and leading to a withdrawal syndrome upon abrupt discontinuation. The euphoria attracts recreational use, and frequent, escalating recreational use of opioids typically results in addiction. Fatal consequences can be caused by an overdose or by concurrent use of opioids with other depressant drugs, resulting frequently in death from respiratory depression. This risk for addiction and fatal overdoses dictates that opioids are mostly controlled substances.
Progress in pretreatment of methadone: an update since 2015
Published in Preparative Biochemistry & Biotechnology, 2023
Methadone (C21H27NO), a µ-opioid receptor agonist and N-methyl-d-aspartate receptor antagonist, since developed between 1937 and 1939 by Gustav Ehrhart and Max Bockmühl, has been widely tested as an opiate drug[1–3]. With similar medical effects to that of morphine (analgesic, miosis, sedative, etc.) but longer action time, (4–8 h one dose) less drug tolerance production and lower drug dependence[4], methadone has become one of the commonly used medicines in WHO Model List of Essential Medicines[5]. For the characteristics of easy production and relatively low price, it has been widely used in the clinical field all over the world. Containing two characteristic benzene ring structures, methadone (6-Dimethylamino-4,4-diphenyl-3-heptanone) has a molecular weight of 345.91[6,7] (Figure 1).
Effect of glucose and sodium chloride mouth rinses on neuromuscular fatigue: a preliminary study
Published in European Journal of Sport Science, 2021
Teng Keen Khong, Victor Selvanayagam, Ashril Yusof
The preservation of MVC by glucose and NaCl mouth rinses may be associated with neural and neuromuscular processes involving the oral cavity (glucose and NaCl receptors), brain, and working muscles. Although the exact mechanism is still unclear, it has been proposed that activation of the anterior cingulate cortex and ventral striatum via the gustatory cortex and orbital frontal cortex following oral CHO stimulation influences motor behaviour (Jeukendrup et al., 2013). In the case of NaCl, activation of ‘salty’ taste receptors in the oral cavity might have an influence on the insular cortex and/or opioid receptor activities (Gosnell & Majchrzak, 1990; Pastuskovas, Cassell, Johnson, & Thunhorst, 2003) which, in turn, could also activate the parasympathetic nervous system that regulates cardiac autonomic activity (Williamson, McColl, & Mathews, 2004) via intracortical communication between the insular cortex and motor cortex, which could improve cycling performance (Williamson et al., 1997). Furthermore, the activity of μ-opioidergic receptors has been shown to play a role in the development of fatigue and is exercise intensity dependent (Hiura et al., 2017; Sidhu et al., 2014). These proposed mechanisms are speculative because the link between the activation of NaCl oral receptors and the brain is yet to be empirically established. Therefore, future work should focus on establishing the role of the insular cortex and modulating the responsiveness of µ-opioid receptors with NaCl mouth rinse during a fatiguing exercise.
Evaluating drugged driving: Effects of exemplar pain and anxiety medications
Published in Traffic Injury Prevention, 2018
Timothy L. Brown, Gary Milavetz, Gary Gaffney, Andrew Spurgin
Use of a benzodiazepine such as alprazolam will result in sedation, memory deficits, and motor and perceptual deficits, all of which negatively affect driving. The inhibitory pharmacological actions induced with benzodiazepine exert significant deleterious effects on driving performance noted in our study. We are unable to identify the exact mechanisms in this study; however, a carefully designed protocol evaluating sedation, motor and perceptional performance, memory, reaction time, and cognitive processing during driving may elucidate why these drugs appear to produce differential effects on driving measures. Hydrocodone, as with all the opioids, produces physiological effects by interacting with the endogenous opioid receptor. The drug binds preferentially to the μ-receptor for pain relief. Weaker binding to other opioid receptors produces side effects including sedation and possibly muscle incoordination. Acute opioid administration produces analgesia, which should not affect driving; side effects may influence alertness and muscle coordination, which could degrade vehicle control and driver ability to respond to emergent traffic conflicts. The lack of an observed effect on driving with a single acute administration to normal healthy subjects does not preclude effects on driving associated with chronic use or in combination with a disease state.