Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030193 (pain)
 261,466 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The properties of bladder afferent neurons in L6 and S1 dorsal root ganglia of adult rats were evaluated after chronic bladder inflammation induced by 2 week treatment with cyclophosphamide (CYP; 75 mg/kg). Whole-cell patch-clamp recordings revealed that most (70%) of the dissociated bladder afferent neurons from control rats were capsaicin sensitive, with high-threshold long-duration action potentials that were not blocked by tetrodotoxin (TTX; 1 microM). These neurons exhibited membrane potential relaxations during voltage responses elicited by depolarizing current pulses and phasic firing during sustained membrane depolarization. After CYP treatment, a similar proportion (71%) of bladder afferent neurons were capsaicin sensitive with TTX-resistant spikes. However, the neurons were significantly larger in size (diameter 29.6 +/- 1.0 micrometer vs 23.6 +/- 0.8 micrometer in controls). TTX-resistant bladder afferent neurons from CYP-treated rats exhibited lower thresholds for spike activation (-25.4 +/- 0.5 mV) than those from control rats (-21.4 +/- 0.9 mV) and did not exhibit membrane potential relaxation during depolarization. Seventy percent of TTX-resistant bladder afferent neurons from CYP-treated rats exhibited tonic firing (average 12.3 +/- 1.4 spikes during a 500 msec depolarizing pulse) versus phasic firing (1.2 +/- 0.2 spikes) in normal bladder afferent neurons. Application of 4-aminopyridine (1 mM) to normal TTX-resistant bladder afferent neurons mimicked the changes in firing properties after CYP treatment. The peak density of an A-type K+ current (IA) during depolarizations to 0 mV in TTX-resistant bladder afferent neurons from CYP-treated rats was significantly smaller (42.9 pA/pF) than that from control rats (109.4 pA/pF), and the inactivation curve of the IA current was displaced to more hyperpolarized levels by approximately 15 mV after CYP treatment. These data suggest that chronic inflammation induces somal hypertrophy and increases the excitability of C-fiber bladder afferent neurons by suppressing IA channels. Similar electrical changes in sensory pathways may contribute to cystitis-induced pain and hyperactivity of the bladder.
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PMID:Increased excitability of afferent neurons innervating rat urinary bladder after chronic bladder inflammation. 1034 Dec 62

Generally, one should keep in mind that if a smoker takes a drug that is metabolized primarily by the CYP 1A2 system, an increased dose may be required. The patient should be closely monitored if he or she is taking several medications that may inhibit or induce the CYP 1A2 isoenzyme. Hepatic enzyme metabolism does not completely explain the effects of smoking on drugs, however, because smokers may have different physiologic responses to pain and sedation that depend on changes in plasma protein binding and in the rate and efficacy of subcutaneous absorption. Most of the few sex/gender-analyzed pharmacokinetic studies in smokers occurred after 1995. It appears that the 1993 changes at the National Institutes of Health and the Food and Drug Administration regarding inclusion of women in clinical trials enabled these examinations to take place. Because smokers--who make up nearly a quarter of the U.S. adult population--tend to consume more medications than nonsmokers, this social habit should be considered one of the most important to impact on drug metabolism in both sexes.
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PMID:Drugs and smoking. 1125 58

Metabotropic glutamate receptors (mGluR) are G-protein-coupled receptors that play a major role in modulatory pathways in the CNS and have been suggested to have pharmacological implications in pain, psychiatric disorders and other neurological states. 3-[(2-Methyl-1,3-thiazol-4-yl) ethynyl]-pyridine (MTEP) is a specific and selective antagonist for the mGluR sub-type 5. Previous studies using rat liver microsomes showed that the major oxidative metabolites of MTEP are a hydroxymethyl metabolite (M1), two oxides (M2 and M4), a thiazole-ring opened metabolite (M3) and CO(2) (M5). In the present study, we examined the metabolism of MTEP in liver microsomes and expressed rat and human CYP isoforms. In rat liver microsomes, metabolic stability studies accurately predicted the in vivo clearance for MTEP. Incubation of MTEP with expressed rat and human CYP isoforms showed that CYP1A and CYP2C isoforms are primarily responsible for the metabolism of this compound. The results suggest that species differences in MTEP metabolism is possible and could contribute to specie-differences in biological effects of the compound.
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PMID:In vitro metabolic studies on the selective metabotropic glutamate receptor sub-type 5 (mGluR5) antagonist 3-[(2-methyl-1,3-thiazol-4-yl) ethynyl]-pyridine (MTEP). 1615 70

There is a need to have predictive biomarkers to test novel experimental medicines in functional gastrointestinal disorders (FGID). The human pharmacodynamic models and biomarkers in functional dyspepsia (part I) and visceral pain (part II) are reviewed, including the general challenges of these two disorders (part I). Part II will also discuss the importance of drug pharmacokinetics and potential of pharmacogenomics, including the influence of CYP metabolism and potential drug interactions. The great heterogeneity of mechanisms potentially responsible for dyspeptic symptoms adds a significant complexity to this FGID. Strategies are needed to identify subgroups most likely to benefit from a specific pharmacological action targeted to one or more mechanisms. Thus, while there are significant challenges in drug development for functional dyspepsia, there is still an important role for pharmacodynamic studies. It remains to be demonstrated that identifying subgroups enhances the response to the pharmacological drug effect. This is feasible as the end points and performance of each test of gastric emptying, accommodation and sensitivity are well characterized. Of these, gastric emptying appears best validated at present, though responsiveness to this biomarker has not yet been translated into positive phase III trials. Eligibility criteria are proposed for selection of patients for functional dyspepsia trials.
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PMID:Challenges in drug development for functional gastrointestinal disorders. Part I: functional dyspepsia. 1662 61

There is a need to have predictive biomarkers to test novel experimental medicines in functional gastrointestinal disorders. The human pharmacodynamic models and biomarkers pertaining to two important conditions are reviewed in a two-part article: functional dyspepsia (part I) and visceral pain (part II). With visceral pain models, the large coefficient of variation in sensation end points in human studies precludes definitive conclusions such as go/no go decisions or dose selection for phase IIb or III studies, unless very large numbers of patients are evaluated in phase IIA pharmacodynamic studies. This renders such pharmacological studies ambitious, or unachievable in a timely fashion. Moreover, the results of tests and clinical trials should be interpreted with greater knowledge of the drug pharmacokinetics, including the influence of CYP metabolism and potential drug interactions. Thus, it is important to identify valid biomarkers of visceral pain for the assessment of treatment response in pharmacodynamic studies. In this second part of a two-part article, we shall discuss the special challenges in developing medications for visceral pain and the general importance of including pharmacokinetic and pharmacogenomic studies in drug development programmes.
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PMID:Challenges in drug development for functional gastrointestinal disorders. Part II: visceral pain. 1662 62

(1) Several classes of antidepressants are available. The main difference between these classes is in their short-term pharmacological effects, leading to different patterns of adverse effects. Some antidepressants, especially tricyclics, have positive risk-benefit balances in the treatment of diabetic neuropathy. (2) Duloxetine, a compound chemically related to fluoxetine, appears to have a short-term mechanism of action similar to that of venlafaxine. In the European Union, duloxetine was first approved for female urinary stress incontinence. Another brand of duloxetine has since been marketed for depression and neuropathic pain in diabetic patients. (3) Duloxetine at a dose of 60 mg once a day showed moderate efficacy in 2 placebo-controlled trials. At this dose, however, there are no other comparative trials. It is therefore not possible to know whether duloxetine is as effective as other antidepressants. (4) Two placebo-controlled trials involving patients with pain due to diabetic neuropathy concluded that a dose of 60 mg/day had efficacy, although of doubtful clinical relevance. In the absence of comparative trials, however, we do not know if this efficacy is even equivalent to that of a tricyclic antidepressant used as an analgesic. (5) In fibromyalgia, a controversial clinical diagnosis, two double-blind placebo-controlled trials involving 207 and 354 patients failed to prove that duloxetine had tangible analgesic efficacy. It is therefore appropriate that this use is not mentioned in the "Indications" section of the summary of product characteristics (SPC). (6) The assessment of duloxetine in depression and neuropathic pain confirms existing data on its gastrointestinal, neuropsychological and hepatic adverse effects. In these trials, duloxetine increased blood pressure in a dose-dependent manner. (7) Duloxetine is metabolized by cytochrome P450 isoenzymes CYP 1A2 and CYP 2D6, creating an important risk of interactions with other drugs. (8) In practice, duloxetine currently has no place in the treatment of depression or diabetic neuropathy. Its efficacy has not yet been demonstrated to be even equivalent to that of other available drugs, and it has too many adverse effects, given this degree of uncertainty.
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PMID:Duloxetine: new indication. Depression and diabetic neuropathy: too many adverse effects. 1712 Dec 11

Liability to spontaneous and experimental pain is genetically determined and there is considerable variability in the antinociceptive effects of drugs commonly used in treating pain conditions and migraine attacks. The causes for variability involve still unknown genetic aspects. Recently, a third gene, SCN1A, was discovered as a cause of familial hemiplegic migraine (FHM). Recent advances in the genetics of pain and pain disorders include the discovery of the role of the sodium ion channel SCN9A in neuropathic pain as well as in inability to experience pain, and of GTP cyclohydrolase (GCH1) in setting the sensitivity to pain in normal individuals and modulating liability to chronic pain. Catechol-O-methyltransferase (COMT) and the cytochrome P450 variant allele CYP3A5 modulate the genetic response to opioid medications in humans. Variability in drug pharmacokinetics and adverse drug reactions of pain medications are also very much related to genetic variation, especially in CYP genes. Pharmacogenomic studies of headache and pain are still in their infancy, but these recent advances in the genetics of migraine and pain arguably hold the promise of individualised treatments and prevention of adverse drug reactions.
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PMID:Recent advances in the pharmacogenomics of pain and headache. 1750 72

It is imperative that primary care clinicians have a thorough understanding of insomnia, because they are often the first point of contact for patients who seek assistance when they have difficulty sleeping. Insomnia may appear with different presentations: sleep onset, sleep maintenances, sleep offset, nonrestorative sleep, or a combination of these symptoms. Untreated symptoms result in clinically significant distress or impairment in social, occupational, or other important areas of following-day functionality. Physicians, pharmacists, and other clinicians should be aware of the conditions that contribute to, are antecedent to, and associated with insomnia. These pathophysiological conditions include advanced age; female gender; respiratory, gastrointestinal, vascular, and rheumatologic pain syndromes; and other conditions such as depression and/or anxiety. Additional health factors contributing to insomnia include chronic pain, stressors, grief reaction, pharmacotherapeutic side effects, lifestyle contributors such as social/recreational drugs, phytopharmaceuticals, and ethanol use. The pharmacotherapy focus in this article is a modified-release formulation of the BZ1 (omega1) receptor agonist zolpidem, zolpidem extended-release. Pharmacokinetic, pharmacodynamic, and safety studies that compare 12.5 mg zolpidem extended-release (Ambien CRtrade markCIV) and 10 mg original zolpidem were initially conducted in healthy volunteers to assess the potential for an improved clinical profile. Zolpidem extended-release (12.5 mg and 6.25 mg extended-release dosage forms) is indicated for the treatment of insomnia characterized by difficulties with sleep onset and/or sleep maintenance. Zolpidem extended-release is devoid of any short-term use limitation and can be prescribed for the duration of medical necessity. The modified-release zolpidem is a two-layer tablet with a biphasic release profile, releasing the first layer immediately, whereas the second layer is released at a slower rate. Plasma concentrations are maintained for a longer period of time versus the immediate-release zolpidem formulation. Pharmacokinetic analysis has also demonstrated that the time to maximum concentration (tmax) and terminal elimination half-life (t1/2) of 12.5 mg zolpidem extended-release are similar to those of 10 mg zolpidem indicating a similar rapid onset of action and an elimination profile that reduced the risk of next-day decrements in performance. Zolpidem's CYP 450 hepatic metabolism uses as a substrate CYP3A4 (major) and 1A2, 2C9, 2C19, and 2D6 as minor pathways. Zolpidem extended-release dosage forms diminish sleep latency, number of awakenings, and wakefulness after sleep onset and augments total time asleep.
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PMID:Zolpidem extended-release: a single insomnia treatment option for sleep induction and sleep maintenance symptoms. 1751 7

Currently, it is known that several chemical agents used or generated by the oil industry are classified as mutagens and/or carcinogens. Among these we have gasoline, diesel, butane gas, styrene, benzene, chloroform, and others. Studies have verified that these chemicals have effects in fertility (abortions, sterility); produce various upheavals, such as dizziness, nausea, muscular pain; and produce chromosomal damage at the DNA level, which in the long or medium run, can develop into cancer and leukemia. The genetic damage in exposed individuals was measured by means of the comet test, chromosomal alterations test, and the study of the CYP 1A1 and MSH2 genes. These methods were applied to determine the genotoxicity of hydrocarbons and their residue in human beings. When conducting these tests on the blood samples of individuals exposed to hydrocarbons (workers of oil companies) and of a control population of the area of study and Quito, it was found that, in effect, the exposed individuals presented a greater amount of damage at the DNA level as well as at the chromosomal level than the individuals from the control populations (P< 0.001). Thus, it can be determined that populations that are exposed to hydrocarbons are susceptible to developing genetic damage. Therefore, risk groups can be determined in certain zones where the oil impact has been greater.
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PMID:Monitoring of DNA damage in individuals exposed to petroleum hydrocarbons in Ecuador. 1899 10

The manifestation of chronic back pain depends on structural, psychosocial, occupational and genetic influences. Heritability estimates for back pain range from 30% to 45%. Genetic influences are caused by genes affecting intervertebral disc degeneration or the immune response and genes involved in pain perception, signalling and psychological processing. This inter-individual variability which is partly due to genetic differences would require an individualized pain management to prevent the transition from acute to chronic back pain or improve the outcome. The genetic profile may help to define patients at high risk for chronic pain. We summarize genetic factors that (i) impact on intervertebral disc stability, namely Collagen IX, COL9A3, COL11A1, COL11A2, COL1A1, aggrecan (AGAN), cartilage intermediate layer protein, vitamin D receptor, metalloproteinsase-3 (MMP3), MMP9, and thrombospondin-2, (ii) modify inflammation, namely interleukin-1 (IL-1) locus genes and IL-6 and (iii) and pain signalling namely guanine triphosphate (GTP) cyclohydrolase 1, catechol-O-methyltransferase, mu opioid receptor (OPMR1), melanocortin 1 receptor (MC1R), transient receptor potential channel A1 and fatty acid amide hydrolase and analgesic drug metabolism (cytochrome P450 [CYP]2D6, CYP2C9).
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PMID:Current evidence for a modulation of low back pain by human genetic variants. 1922 64


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