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)

Histamine-sensitive nerve endings are assumed to terminate in the superficial epidermis. Heat-sensitive nociceptors that are excited by brief carbondioxide-laser pulses must also terminate within the epidermis, because this infrared radiation has an extinction length of about 10 microns. We now compared laser heat stimuli (10 W, 50 ms, 20 mm2) with intradermal injections of histamine (10(-10) to 10(-8) mol) in their capacity to cause cutaneous vasodilatation (flare) in awake human subjects. Cutaneous blood flow was measured with a two-channel laser-Doppler device. The radiant heat pulses caused a transient cutaneous vasodilatation that spread at least 15 mm from the stimulus site. There was no visible flare and vasodilatation could only be detected by laser Doppler measurements. Although the heat pulses elicited enough nociceptor activity to be perceived as moderately painful, the magnitude of the vasodilatation was smaller and its duration shorter than after the smallest dose of histamine. In contrast, nociceptor activation by heat is usually stronger than by histamine. These data indicate that flare and pain are two different aspects of cutaneous small fiber function.
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PMID:Vasodilator flare due to activation of superficial cutaneous afferents in humans: heat-sensitive versus histamine-sensitive fibers. 143 31

Factors involved in the pathophysiological changes such as severe pain, burning sensation, redness, swelling and edema in case of the scorpion L. laevifrons were investigated. The presence of pain-producing autacoids histamine 2.1 +/- 0.18 micrograms/mg and 5-HT 0.23 +/- 0.1 micrograms/ml was confirmed by thin layer chromatography and bioassay. Histamine releasing substance was detected in vitro in the chopped guineapig lung. Venom also contained hyaluronidase 5 x 10(-4) N-acetyl-D-glucosamine released/h/mg, which facilitates spread of the toxic principles in the tissues. It is concluded that histamine, 5-HT, histamine-releasing factor and hyaluronidase are partly involved in the pathophysiological changes induced by the venom. It is suggested that mepyramine and cyproheptadine may prove useful in the management of scorpion envenomation.
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PMID:Histamine, 5-HT & hyaluronidase in the venom of the scorpion Lychas laevifrons (Pock). 170 25

Psychophysical measurements of itch and itchy skin ("alloknesis"--itch produced by innocuous mechanical stimulation) were obtained in human volunteers following intracutaneous or subcutaneous injections of histamine or papain into the volar forearm. Histamine and papain were given in doses of 0.1, 1, or 10 micrograms in 10 microliters of saline. The effects of the depth of injection and of skin temperature on the latency, magnitude, and duration of itch were examined. Also, dose-response functions were obtained for the area of alloknesis produced by intracutaneous injections of histamine. Finally, the neural mechanisms underlying the spread of alloknesis were investigated via local anesthesia of the skin. Intracutaneous and subcutaneous injections of histamine, but not papain, produced a sensation of itch without pain. The latency of itch was shorter after an intracutanous than after a subcutaneous injection of histamine. The mean latencies of itch produced by a 1-microgram dose were 9.5 and 23.0 sec for intracutaneous and subcutaneous injections, respectively. No differences were observed in the magnitude or duration of itch. Similarly, the latency of itch was increased when the skin temperature at injection site was lowered to 15 degrees C, whereas the magnitude and duration of itch were unaffected. Intracutaneous and subcutaneous injections of histamine produced similar areas of alloknesis. However, the magnitude and duration of alloknesis were dependent on dose. The mean maximum areas of alloknesis produced by intracutaneous injections of 0.1, 1, and 10 micrograms of histamine were 28.3, 47.2, and 43.8 cm2, respectively. Alloknesis was present at 2 min after injection, increased to a maximum area without 10 min, and then gradually decreased during the next 25-40 min.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Psychophysical studies of the itch sensation and itchy skin ("alloknesis") produced by intracutaneous injection of histamine. 176 23

1. The aim of this investigation was to study the peripheral neural mechanisms of the C-fiber-mediated modalities of burning pain and itch by the use of microneurography of human unmyelinated afferents. 2. Sixteen stable recordings of single C-fibers and 6 multiunit recordings were obtained from the superficial radial nerves of volunteers. All units were excited by stimulating their receptive fields with von Frey bristles (range 10-600 mN), and all but four units were also driven by radiant heat stimulation. 3. Histamine was iontophoretically applied to the receptive fields of these units for 20 or 30 s and was found to provoke itching sensations lasting several minutes, together with wheal and flare responses. Subsequently a solution containing 20 or 30% mustard oil was applied to the receptive field of the respective unit, which provoked a sensation of burning pain. 4. One-half of the units were excited by histamine, and the median discharge rates derived from interspike intervals ranged from approximately 0.1 to 0.8 Hz. Mustard oil-induced activity was observed in all histamine-sensitive units and also in three single units and in one multiunit recording that revealed no histamine response. Median interval-derived discharge rates ranged from 0.2 to 1.2 Hz. 5. Analysis of the interspike interval distribution and of the autocorrelation function derived from the chemically induced discharges of single units provided no evidence for an encoding of itch and burning pain in different discharge patterns of units responding to histamine and to mustard oil.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Discharge patterns of human C-fibers induced by itching and burning stimuli. 191 73

Pancreatic enzyme therapy may be beneficial to all patients with chronic pancreatitis, even those in whom the condition is very mild. The goal of enzyme therapy should be to restore normal gastrointestinal physiology as completely as possible. Monitoring of body weight is recommended as the main measure of treatment efficacy. Most pancreatic enzyme preparations presently employed are porcine in origin and must meet certain standards of quality for human consumption. The amount of active lipase in the duodenum determines the quantity of enzymes to be given. An appropriate diet is also important for relieving symptoms of pancreatic insufficiency and improving nutritional status. Although administration of large amounts of proteases has provided pain relief in some patients, the rationale for using enzymes to relieve pain in chronic pancreatitis has not been generally accepted. Gastric acid plays a role in malabsorption, since administered enzymes may be destroyed by gastric acid. Also, acidic conditions in the duodenum decrease the efficacy of pancreatic enzymes administered with meals. Histamine-H2-receptor antagonists may decrease gastric acidity but there are certain drawbacks to long-term use of these agents. The use of enteric-coated microspheres overcomes many of the problems associated with enzyme destruction. Patients with chronic pancreatitis display considerable individual variation in their treatment requirements. Therapy must be tailored to meet the need for adequate disease control as well as for social and emotional acceptability by the patient. The attending physician and the patient share the responsibility for maintaining appropriate therapy.
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PMID:Theory and practice in the individualization of oral pancreatic enzyme administration for chronic pancreatitis. 270 51

New sensitive antisera against histamine were used to study the distribution of histamine-immunoreactive nerve fibers in the spinal cord of several mammalian species. Tissues were fixed with carbodiimide by transcardiac perfusion or immersion. A few immunoreactive nerve fibers were found in the cervical spinal cord of the rat in the superficial laminae of the dorsal horn, around the central canal and scattered in the anterior horn. The density of immunoreactive fibers in the cervical spinal cord of the guinea pig and tree shrew was higher, but still low. The densest networks of histamine-immunoreactive fibers were seen in the cervical spinal cord of the pig. The laminar distribution of histamine-immunoreactive fibers was similar in all species. Histamine-immunoreactive fibers were densest in lamina X, followed by laminae I-II. Scattered fibers were also seen in the white matter in the lateral and posterior funiculus in the pig. In the rat and the guinea pig, no histamine-immunoreactive cell bodies were seen in the spinal sensory ganglia. The results suggest that the histamine-immunoreactive nerve fibers in the spinal cord may originate from the brain, probably from the posterior hypothalamus, and the fiber projection is more extensive in higher mammalian species. The role of histamine in the spinal cord is not known, but it may be involved in, e.g., pain sensation.
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PMID:Histamine-immunoreactive nerve fibers in the mammalian spinal cord. 271 84

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

In spite of the research that has been performed, pruritus remains a poorly understood sensation. It is important to remember that the majority of information presented here is derived from observations of human subjects. One can only speculate as to how much of this information can be extrapolated to pruritus in animals. Pruritus is closely intertwined with pain and touch. Pain and pruritus sensations are carried on A delta and C fibers, ascend on the lateral spinothalamic tract, and terminate in various brain centers, including the thalamus and the cortex. The gate control theory of pain and pruritus describes the substantia gelatinosa cells as "swinging gates" to modify peripheral input and result in stimulation of higher centers. Central factors reduce or amplify the perception of these cutaneous sensations. Histamine is the classic mediator of pruritus, although it is still unknown whether a final common mediator of pruritus exists. Numerous other mediators include proteases, peptides, substance P, opiate peptides, prostaglandins, and leukotrienes. These may have pruritic properties directly, or may act as histamine liberators to cause pruritus.
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PMID:Pathophysiology of pruritus. 305 50

Plasma from persons with hereditary angioneurotic edema readily developed the capacity to increase vascular permeability and to induce the isolated rat uterus to contract. Both activities resided in a small, heat-stable molecule that was apparently a polypeptide. Crude preparations of the polypeptide were inactivated during incubation with trypsin. They also failed to produce pain and erythema, but caused markedly increased vascular permeability in human skin. These characteristics differ from those of bradykinin, from which crude preparations of the polypeptide could also be distinguished by electrophoretic mobility and paper chromatographic behavior. Proof that the polypeptide is truly different from bradykinin must await its further purification. Histamine played no role in the activities observed. Although the enzymes functioning to release the permeability factor and kinin activities in hereditary angioneurotic edema plasma were not clearly defined, one or more plasma enzymes other than C'1 esterase presumably participated either in conjunction with C'1 esterase or in pari passu events to release the polypeptide mediating these activities.
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PMID:Permeability-increasing activity in hereditary angioneurotic edema plasma. II. Mechanism of formation and partial characterization. 581 21

Intracerebroventricularly administered dimaprit decreased the depth of urethane anaesthesia. Ventilatory stimulation, positive corneal reflex and increased susceptibility to pain were observed. Furthermore, dimaprit decreased the lethal effect of large doses of urethane. The analeptic property of dimaprit was not shared by the potent H2-receptor agonist, impromidine, Histamine increased ventilatory tidal volume but no other stimulatory effects were observed. These findings suggest that the analeptic effects of dimaprit were not mediated by H2-receptors. Among the analeptic effects of dimaprit, only the protection against urethane toxicity was antagonized by metiamide. However, this phenomenon appeared to be due to the nonspecific interaction between the three bradypnoeic drugs metiamide, dimaprit and urethane. The histamine-induced increase in ventilatory tidal volume was not antagonized by diphenhydramine or metiamide, suggesting the existence of a novel histaminergic mechanism in the central nervous system.
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PMID:Analeptic effect of centrally administered histamine H2-receptor agonist dimaprit but not impromidine in urethane-anesthetized rats. 612 2


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