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Query: UMLS:C0030193 (pain)
 261,466 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 5-hydroxytryptamine (5HT) precursors tryptophan and 5-hydroxytryptophan had no significant effect on the behavior of rats in the formalin test when given by themselves. However, both compounds significantly attenuated the analgesic effect of morphine in the formalin test. The 5HT antagonist methysergide enhanced the antinociceptive effect of morphine but systemic 5HT had no effect. Assays of whole brain and spinal cord indoles revealed different patterns as a result of tryptophan or 5-hydroxytryptophan loading. The effect common to both treatments was an increase in brain 5HT. There was no effect of morphine on any measure. Formalin injection by itself did not alter indole levels in the brain or spinal cord. Our results, taken in conjunction with previous work, suggest that 1) 5HT in the spinal cord does not influence pain perception in the formalin test and 2) 5HT in the brain can antagonize morphine analgesia in the formalin test. We conclude that there may be circumstances in which the use of 5HT precursors for clinical pain management may be contraindicated.
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PMID:Effect of 5-hydroxytryptamine precursors on morphine analgesia in the formalin test. 247 42

The authors investigated the cerebral metabolism of tryptophan in patients suffering from malignant pain by means of CSF dosage of tryptophan (Trp), 5-hydroxytryptophan (5-HTP), serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA). The level of 5-HIAA in patients with pain was 66.48 +/- 13.67 ng/ml, while in those without pain was 25.05 +/- 13.25 ng/ml; the difference was statistically significant, p = 0.001. Trp, 5-HTP and 5-HT levels did not register significant differences in the two groups of patients, although a tendency to lower values was seen in patients with pain, supporting the hypothesis of increased turnover of this metabolic pathway in cancer patients. A statistically significant inverse correlation was also found between cerebral Trp levels and pain levels measured on the Scott-Huskisson visual analogue scale. The data obtained confirm the importance of the cerebral serotoninergic pathway in pain modulation and the interest which CSF analysis may have for the assessment of patients suffering from pain.
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PMID:Cerebral tryptophan metabolism in humans in relation to malignant pain. 248 29

We have investigated the possible associations between the demographic, clinical and psychological characteristics of 80 patients with low back pain and the CSF levels of 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA) and 3-methoxy-4-hydroxyphenylglycol (MHPG), the principal central nervous system metabolites of serotonin, dopamine and noradrenaline, and of tryptophan, the amino acid precursor of serotonin. Neither the clinical measures nor the psychological characteristics were significantly correlated with the CSF neurochemistry. Therefore the hypothesis about an intimate relationship between monoaminergic neurotransmission and the experience of chronic low back pain was not confirmed. Among the other factors studied, body height contributed most to the variance in both 5-HIAA and HVA concentrations; the levels of MHPG increased with age.
Pain 1985 Jan
PMID:Neurotransmission and the experience of low back pain; no association between CSF monoamine metabolites and pain. 258 Feb 62

Free plasma tryptophan levels in patients with fibrositis syndrome were measured by Moldofsky and Warsh with the view that the pathogenesis of fibrositis syndrome might involve a functional deficiency of serotonin. The hypothesis was supported by the finding of an inverse relationship between tryptophan concentration and the severity of musculoskeletal pain. Our study examined the total serum amino acid pool in fibrositis syndrome. Twenty patients with primary fibrositis syndrome and matched normal controls were evaluated clinically. After denaturation of macromolecules, serum amino acids were quantitated by automated analysis. Patients with fibrositis syndrome exhibited significantly lower levels of total serum tryptophan (p = 0.002), as well as 6 other amino acids: alanine (p less than 0.0005), histidine (p = 0.001), lysine (p = 0.02), proline (p = 0.039), serine (p = 0.028), and threonine (p = 0.013). These findings support the serotonin deficiency hypothesis for fibrositis syndrome pathogenesis but also imply a more generalized defect in amino acid homeostasis among affected individuals.
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PMID:Serum amino acids in fibrositis/fibromyalgia syndrome. 260 10

We have compared levels of albumin and serum amino acids in a group of 87 recent admissions to a nursing home, average age 83 years, with a group of healthy moderately old subjects, average age 69 years. We found that the nursing home group was characterized by decreased levels of albumin, by increased total levels of the measured amino acids, and by increased levels of the nonessential amino acids. In contrast, there were no significant group differences in the essential amino acids. Among the nursing home patients, there was a negative correlation between essential amino acids and disability, consistent with nutritional deficits in the more disabled patients, and a positive correlation between essential amino acids and subjective complaints of pain, suggesting that pain is associated with breakdown or mobilization of endogenous protein stores. Though the nursing home patients had decreased serum levels of tryptophan, there was no association between serum tryptophan or other variables that could be related to the availability of tryptophan for transport into brain, with ratings of either depression or pain. Glutamine levels were significantly increased in the nursing home residents, and among these patients they were positively correlated with measures of cognitive impairment.
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PMID:Amino acid levels in elderly nursing home residents. 263 18

1. Tryptophan increases 5HT synthesis, but the extent to which it increases 5HT release and therefore 5HT function is unclear. 2. The possibility that increased 5HT levels will lead to increased 5HT release is enhanced when 5HT neurons are firing at a higher rate. The rate of firing of 5HT neurons is increased as the level of behavioral arousal increases. Thus, altered tryptophan levels will be more likely to influence brain function at higher levels of arousal. 3. In the rat, tryptophan administration increased CSF 5HT appreciably when the animals were aroused by being put in the dark, but not when they were left in a lighted room. 4. In monkeys, the level of behavioral arousal does seem to influence the effect of altered tryptophan levels on aggression. This is consistent with the fact that altered tryptophan levels had no effect on aggression in normal subjects, but that tryptophan had a therapeutic effect in pathologically aggressive patients. 5. The confusing literature on the antidepressant effect of tryptophan can, to some extent, be explained by considering the circumstances in which tryptophan administration will lead to increases in 5HT release as well as increases in 5HT synthesis. 6. Although in some circumstances tryptophan can decrease pain perception by activation of spinal 5HT pathways, when it was given to postoperative patients it attenuated morphine analgesia by activation of a 5HT pathway in the brain. 7. The effect of altered tryptophan levels depend critically on the circumstances in which it is given.
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PMID:Tryptophan availability, 5HT synthesis and 5HT function. 266 90

Effects of L-tryptophan supplementation and dietary manipulation were tested on patients with chronic myofascial pain around the temporomandibular joints. In this study, however, reduction of chronic pain reported in previous similar studies was not duplicated. No significant reduction in pain was noted in the groups receiving tryptophan and dietary manipulation compared with control groups.
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PMID:The effect of L-tryptophan supplementation and dietary instruction on chronic myofascial pain. 273 42

From November 1979 to May 1982, I had the "honor" of serving time at Evin political prison, Teheran Iran. Evin is the historical prison which has set the pace of revolution in the country. At Evin it was discovered that increased regular intake of water improved the clinical picture of peptic ulcer disease. One of the main components of this picture was pain of varying severity, sometimes very severe indeed. Theoretical research to find the physiological reasons for the observed effect of water, in a condition currently classified as disease, has revealed a neurotransmitter, an osmoregulator, a water intake promoter status and a role for histamine. The action of histamine seems to be coupled to the efficient function of the cation pumps. Histamine and serotonin are involved in the regulation of the body's water balance. Cellular "free water" insufficiency produces a disturbance of tryptophan metabolism; it is this disturbance and induced functional deficiency altering the homeostatic balance that produces pain and eventually tissue transformation and/or damage. This pain is being introduced as a signal system denoting free water deficiency of the cell and, therefore, it should be classified as thirst pain. Histamine and the reninangiotensin system also coordinate the water intake and sodium balance of the body. With the induction of renin-angiotensin system for increase in water intake, threshold rates for water intake and the threshold rates for raising blood pressure seem close.
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PMID:Pain: a need for paradigm change. 282 4

Using voltage-time-dependent negative resistance characteristics of Voltage-Current curves of excitable cell membranes estimated without using artificial voltage clamp method, the author made a quantitative analysis of excitability of cell membranes and different conditions of transmembrane action potentials as a bias voltage to the negative resistance of the excitable cell membrane. The pacemaker cells were classified as "Astable Oscillators" and nonpacemaker excitable cells as "Monostable Oscillators," and application of a rapidly changing electromagnetic field to the cells was analyzed as a means of stimulating the cells. The understanding of the 10 essential electrical parameters is highly desirable for safe and effective electrical stimulation. Among these, emphasis was placed on the often neglected, important electrical parameters of "output impedance" of stimulation pulse wave complexes for + and - polarity components, as well as the importance of capacitive current (Ic = C.dV/dt) which depends on rise time as well as fall time of the stimulation pulse wave, and undesirable side effects of electrolysis phenomena due to excessive D.C. current. The difference and similarity between TENS (Transcutaneous Nerve Stimulation) and TES (Transcutaneous Electrical Stimulation), TENMS (Transcutaneous Electrical Nerve and Muscle Stimulation) or TMS (Transcutaneous Muscle Stimulation) was discussed. The author's clinical study indicated that effective TES (TENMS)--characterized by effective muscle contraction without creating pain with a pulse repetition rate approximately the same as the heart rate of the individual--can often give superior beneficial effects in improvement of micro-circulation and subsequent relief of pain and other symptoms compared with TENS that creates stimulation of large diameter sensory nerve fibers without creating significant muscle contraction. Such improvement is often accompanied by the abolishment of the pain with disappearance of local substance P and increase in local serotonin with disappearance of local L-tryptophan.
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PMID:Basic electrical parameters for safe and effective electro-therapeutics [electro-acupuncture, TES, TENMS (or TEMS), TENS and electro-magnetic field stimulation with or without drug field] for pain, neuromuscular skeletal problems, and circulatory disturbances. 289 68

L-Tryptophan (L-TP) has been used in migraine and other pain conditions. The mechanism underlying the analgesic effect is still partly undefined. In this study the effects of subchronic administration of L-5-hydroxy-tryptophan (L-5HTP) (with and without carbidopa) on plasma beta-endorphin (beta-EP) levels and subjective pain threshold and tolerance were investigated in seven healthy volunteers. To measure also an objective indicator for pain, the nociceptive flexion reflex threshold was studied. L-5HTP treatment with and without carbidopa administration increased beta-EP levels significantly (p less than 0.05). L-5HTP plus carbidopa induced an increase in beta-EP significantly (p less than 0.05) higher than that after L-5HTP alone. Neither subjective pain threshold and tolerance nor RIII threshold was modified by either treatment. Our data seem to point to the existence of a complex linkage between plasma opioid levels and pain perception.
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PMID:Effects of L-5HTP with and without carbidopa on plasma beta-endorphin and pain perception. Possible implications in migraine prophylaxis. 294 52


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