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Query: UMLS:C0344307 (analgesia)
 28,200 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous research implicates an endogenous central pain inhibitory mechanism in opiate analgesia, analgesia produced by focal electrical stimulation of the brain, and acupuncture analgesia. This investigation evaluates the possibility that analgesia produced by hypnosis is also mediated by such a mechanism. Results suggest that hypnotic analgesia is unlikely to involve this central pain inhibitory mechanism since hypnotic analgesia is not altered by naloxone hydrochloride, a specific narcotic antagonist. Results further demonstrate that the hypnotic procedure used produces an unusually effective and reliable increase in pain threshold. This finding generalizes to the control of clinical dental pain, and suggests that hypnotic pain control is a more widespread phenomenon in the population than has been thought.
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PMID:Evaluation of the efficacy and neural mechanism of a hypnotic analgesia procedure in experimental and clinical dental pain. 33 20

1. Single doses (500 and 1000 mg) of both buffered aspirin and aspirin tablets were compared with placebo in a randomised double-blind trial of parallel design in patients with postoperative pain after third molar surgery. 2. Only buffered aspirin 500 mg provided significant pain relief (P = 0.016) during the 5 h investigation period. 3. A significant correlation (P = 0.004) was observed between overall pain scores after the various aspirin treatments and aspirin esterase activity. 4. Buffered aspirin preparations afforded a slight advantage over aspirin tablets in the control of postoperative pain after third molar surgery. However, the duration of analgesia was short (approximately 2 h). 5. Aspirin esterase activity appears to be an important determinant of the drug's efficacy in postoperative dental pain.
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PMID:An evaluation of buffered aspirin and aspirin tablets in postoperative pain after third molar surgery. 157 68

Piroxicam, a NSAID with a proved analgesic and antiphlogistic efficacy, largely used in rheumatic-orthopedic pathologies, has an antalgic action also in extra-rheumatic pathologies, such as postoperative and dental pain and primary dysmenorrhea. This is probably due both to a peripheral mechanism, at the injured site level, which is particularly widespread, and goes from prostaglandin inhibition to suppression of the synthesis of different algesiogenic substances (oxygen free radicals, lytic enzymes), and to a direct non endorphin-mediated action at central level. The data base considered in this review, concerning piroxicam in extra-rheumatic analgesia, is of about 2,500 patients, in 26 clinical studies, mostly with an experimental double-blind placebo-controlled design or vs other NSAIDs. The doses ranged from 5 to 40 mg in a single administration: the doses of 20 and 40 mg showed an immediate analgesic effect, with the onset of analgesia within 30 min./1 hour from the administration. Analgesic activity was intense, comparable or superior to that of other drugs (aspirin, codeine, other NSAIDs) and more prolonged, often lasting as long as 24 hours. Tolerability of this data base was very satisfactory and comparable to that of the placebo, incidence of side effects being negligible.
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PMID:[Piroxicam in analgesia]. 182 75

The purpose of this study was to examine in man the analgesic effect of non-segmental electroacupuncture (EA) limited to a single point (Hoku hand point) and the influence of naloxone using an original modified electrical dental pain test. Results in the literature are still contradictory as to the degree and specificity of acupuncture analgesia and its opioid nature. Acupuncture techniques as well as experimental pain models are factors accounting for the discrepancies in the results. For this reason, we designed an experimental pain test characterized by a high degree of specificity, validity and reliability. We chose optimal conditions for eliciting specific acupuncture effect, i.e. non-segmental, low frequency and painful intensity range. A cross-over repeated measure experimental design was used. Five normal trained subjects participated in 65 sessions under four conditions (control, EA, EA+naloxone, EA+placebo). Changes in experimental dental pain thresholds served as indices of analgesia. The results indicated a 27% pain threshold increase after 30 minutes of EA stimulation (p less than .0001), with no differential effect between pain detection (mild pain sensation) and pain discomfort (strong pain sensation). This increase was partially blocked by the double blind injection of 0.8 mg naloxone IM (p less than .005). The experiment was designed in such a way as to prevent the occurrence of a stress analgesic effect. The endogenous opioid system was shown to be partially involved in acupuncture analgesia. Other mechanisms of action are discussed in view of the literature findings.
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PMID:Influence of naloxone on electro-acupuncture analgesia using an experimental dental pain test. Review of possible mechanisms of action. 288 37

Although dihydrocodeine (DF118) is widely prescribed by general dental practitioners, there is little evidence that it is successful in controlling post-operative dental pain. Ibuprofen is known to be effective in this situation. A single dose, double-blind study was carried out in 148 patients to compare 400 mg ibuprofen with 30 mg dihydrocodeine and placebo for treating moderate to severe pain following the removal of unilateral, impacted mandibular third molar teeth under local anaesthesia. An additional dose of either ibuprofen or dihydrocodeine was available after 2 hours. The post-operative ibuprofen reduced pain and produced more pain relief than dihydrocodeine or placebo. Furthermore, fewer patients receiving ibuprofen took additional analgesic at 2 hours. Patients who received ibuprofen as supplementary medication also experienced less pain and had greater pain relief than those receiving dihydrocodeine as supplementary medication, even when their post-operative treatment had been placebo. More patients reported the medication as having been effective if they took ibuprofen either post-operatively or as supplementary analgesia. Ibuprofen is an appropriate analgesic for treating post-operative dental pain.
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PMID:A comparison of ibuprofen and dihydrocodeine in relieving pain following wisdom teeth removal. 292 Jan 33

The severity of postoperative dental pain can be variable depending on the type of procedure. Both centrally acting and peripherally acting analgesics, such as nonsteroidal anti-inflammatory drugs (NSAIDs), aspirin, and acetaminophen are used. NSAIDs are generally better suited to ambulatory outpatients. The most commonly used postoperative dental pain model includes patients who have undergone surgical removal of impacted third molar teeth. The analgesic efficacy of piroxicam in this pain model was studied both in the United States and in foreign centers. The foreign studies suggest that piroxicam at 20-mg doses produces analgesia in patients with postoperative dental pain. Seven single-dose, randomized, double-blind trials of 798 patients in the United States more clearly evaluated the efficacy of piroxicam. These studies used various doses of piroxicam (5, 10, 20, and 40 mg), aspirin 648 mg, and placebo. Safety results showed that a wide range of piroxicam doses were safe when administered in single doses. Although neither piroxicam 5 mg nor 10 mg produced clinically significant analgesia, 20-mg and 40-mg doses were significantly superior to placebo and both were comparable with aspirin 648 mg over the initial six hours. Piroxicam 20 mg and 40 mg, however, produced significantly longer durations of analgesia than aspirin 648 mg, and it appears that the analgesic effect of piroxicam may extend for up to 24 hours in a substantial proportion of patients.
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PMID:Analgesic efficacy of piroxicam in postoperative dental pain. 328 10

Previous studies have shown that muscle exercise and low frequency transcutaneous nerve stimulation (TNS) give rise to an analgesic effect in humans and animals. Endorphin has been proposed to mediate this analgesia. In this investigation, the effect of muscle exercise and low frequency TNS, on dental pain thresholds was studied and the possible involvement of endorphinergic mechanisms was investigated using naloxone as an antagonist. Dental pain thresholds were measured in 11 volunteers following leg or arm exercise and after low frequency TNS of the hands or face. After exercise (20 min) or stimulation (30 min) either 0.8 mg naloxone (2 ml) or saline (2 ml) was injected i.v. in a double-blind fashion. Pain thresholds were measured repetitively before and after exercise or stimulation. Both leg and arm exercise increased pain threshold. Stimulation of the hands also increased pain threshold, but less than arm exercise. A marked increase in pain threshold was seen after face stimulation. These changes in pain threshold were unaffected following injections of either naloxone or saline, except for an early and short-lasting reduction when naloxone was injected following arm exercise. The increases in pain threshold following muscle exercise and after low frequency TNS, showed similarities suggesting that a common mechanism might be involved. The pain threshold increase after arm exercise could only be partially mediated by endorphinergic mechanisms.
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PMID:Effects of naloxone on dental pain threshold following muscle exercise and low frequency transcutaneous nerve stimulation: a comparative study in man. 348 46

Recent animal studies indicate that vasopressin has analgetic properties. The aim of this study was to find out if lypressin, a vasopressin analogue, produces analgesia in man. The effect of i.n. lypressin (5 and 10 I.U.) on experimental pain was tested in healthy humans. The lower dose proved high enough to produce a significant antidiuretic effect. Lypressin did not have any marked analgetic effect at these doses either on ischaemic, cutaneous thermal, or dental pain. The results indicate that lypressin cannot be used for pain relief in man at doses low enough not to produce a hazardous water retention.
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PMID:Human pain thresholds after the application of lypressin, a vasopressin analogue. 362 76

Unilateral trigeminal tractotomy was carried out at the level of the obex, just rostral to the subnucleus caudalis, in five young adult Macaca fascicularis monkeys. The animals had been trained previously to perform a behavioral shock avoidance task in response to electrical stimulation of dental pulp and facial skin. Tractotomy produced an elevation in the stimulus strength which elicited escape behavior when facial skin was stimulated but not when the tooth pulp was stimulated. Unit activity, evoked by electrical stimulation of the tooth pulp and facial skin as well as innocuous and noxious mechanical stimulation of orofacial regions, was recorded from neurons in the trigeminal main sensory nucleus and the subnuclei oralis and interpolaris of the spinal nucleus 8 to 12 weeks after tractotomy. Primary afferent input to these nuclei is unaffected by the tractotomy which is located more caudally. The tractotomy interrupts primary afferent input into the trigeminal nucleus caudalis and also intranuclear connections between caudalis and the more rostral nuclei. Forty-one units contralateral and 47 ipsilateral to the tractotomy were studied. Thirty-six of the units responded only to low-threshold mechanical or electrical stimulation of orofacial zones, 46 were responsive to innocuous mechanical and electrical stimulation of orofacial zones and also to electrical stimulation of the dental pulp. Six units responded only to dental pulp stimulation. No statistically significant differences between the populations of neurons ipsilateral and contralateral to the tractotomies were found relating to the size or location of the peripheral receptive fields, latencies, thresholds, mean firing densities, or responsiveness to the various forms of stimulation. The behavioral results suggest that trigeminal relay neurons rostral to the obex are able to signal dental pain sensation, and the physiological studies confirm that the firing of such neurons is unaffected by tractotomy. The physiological studies demonstrate that the firing patterns of relay neurons activated by natural and electrical cutaneous facial stimuli and which are located in trigeminal brain-stem nuclei rostral to the obex are also not affected by tractotomy. The cutaneous facial analgesia observed after tractotomy thus appears to be due to deafferentation of relay neurons in trigeminal nucleus caudalis rather than to alterations in coding patterns in rostrally located trigeminal neurons due to interruption of the intratrigeminal pathway between the caudal and rostral nuclear groups.
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PMID:Neuronal responses in rostral trigeminal brain-stem nuclei of macaque monkeys after chronic trigeminal tractotomy. 376 Sep 61

This communication presents some insights into the controversies and complications in experimental pain research using laboratory animals. In particular, I have singled out two experimental pain indices that are used in my laboratory for a decade, viz, dental pain model and hot-plate algesiometric assay for discussion. Using these two models, my colleagues and I have identified that morphine may promote analgesia by enlisting synergistic actions from the central cholinergic and dopaminergic systems, in a process that involves shifting of balance between various neurotransmitter systems. We confirmed the medullary nucleus reticularis gigantocellularis as a site for clonidine- and morphine-induced and stimulation-produced antinociception. Finally, a progressive increase in pain sensitivity and a gradual reduction in the analgesic potency of morphine and clonidine are unveiled in aging rats.
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PMID:Some experimental pain indices and their applications in the study of analgesic mechanisms. 403 66


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