Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P20366 (substance P)
 21,176 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neurogenic inflammation, in its original definition, the plasma leakage induced by stimulation of peripheral sensory nerves, occurs in the postcapillary venules of the skin and airways. Plasma leakage is accompanied by increased blood flow, which results from dilatation of arterioles. In skin, these phenomena are manifested as wheal and flare, respectively. Both phenomena are mediated by neuropeptides released from capsaicin-sensitive unmyelinated sensory nerve fibers. Substance P is the primary mediator responsible for plasma leakage, acting via tachykinin NK-1 receptors, whereas both calcitonin gene-related peptide and substance P induce vasodilatation. Sensory nerve transmitters also cause release of histamine from mast cells, which contributes substantially to plasma leakage in the skin, but less so in the airways. Substance P causes an increase in vascular permeability as a result of the focal, transient, and fully reversible formation of gaps, approximately 0.5 to 1.5 microns in diameter, located in the intercellular junctions of endothelial cells. The gaps can be visualized by silver nitrate staining of the endothelial cell borders, by lectin staining, or by scanning and transmission electron microscopy. Neurogenic inflammation can be inhibited by preventing the stimulation of sensory nerves, by presynaptic inhibition of neuropeptide release from sensory nerves, or by blocking neuropeptide receptors. The formation of endothelial gaps can also be inhibited by anti-inflammatory drugs that stabilize endothelial cells, such as beta-adrenergic agonists and steroids.
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PMID:Neurogenic inflammation in skin and airways. 948 20

Atopic dermatitis is a pruritic inflammatory skin disorder, involving immunological and non-immunological factors. Substance P seems to be involved in the pathogenesis of atopic dermatitis. Substance P-containing nerve fibers are increased in the lesional skin of patients with atopic dermatitis and a reduced weal and flare reaction to intradermal injection of substance P has been observed. We investigated the distribution of substance P receptors in the involved skin of patients before and after single or repetitive UVA irradiations. Our results indicate that substance P receptors of the NK-1 subtype are expressed on blood vessels and on epidermal keratinocytes of involved skin of patients with atopic dermatitis. UVA irradiations did not modify the epidermal distribution of substance P receptors but decreased their expression intensity on blood vessels. UVA irradiations seem to decrease skin inflammation through the modulation of NK-1 receptor expression on endothelial cells.
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PMID:Modulation of cutaneous SP receptors in atopic dermatitis after UVA irradiation. 953 83

We have investigated the possible existence of the H3 histamine receptor in human skin with the highly selective ligands R alpha methylhistamine (RAMHA) (H3 agonist) and thioperamide (H3 antagonist). We compared the intradermal effects of RAMHA with histamine, and studied their potential modulation by the H1 antagonist terfenadine, and H2 antagonist cimetidine. The effects of RAMHA and thioperamide on codeine phosphate-, substance P- and histamine-induced weal and flare responses were also studied. RAMHA produced dose-related weal and flare responses that were approximately 10- and fivefold less, respectively, than responses to histamine. Flare responses to RAMHA were significantly inhibited by oral terfenadine (P < 0.05). Weal and flare responses to histamine after oral cimetidine showed much intersubject variation, and cimetidine did not significantly alter either RAMHA- or histamine-induced weal and flare responses. Codeine phosphate-, substance P- and histamine-induced responses were not significantly affected by concurrent administration of RAMHA. Thioperamide was not found to influence codeine phosphate-, substance P-, RAMHA- or histamine-induced effects. RAMHA induces vascular (weal and flare) responses in human skin, and these responses are partially inhibited by terfenadine. There is a trend for RAMHA to have an additive effect to the weal induced by substance P and histamine, although our results largely do not reach statistical significance. Thioperamide does not affect the vascular responses to RAMHA, codeine phosphate, histamine or substance P. We cannot conclude that the effects of RAMHA are induced by H3 receptors on cutaneous endothelial or mast cells.
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PMID:The intradermal effects of the H3 receptor agonist R alpha methylhistamine in human skin. 964 Mar 66

Itching reflects a distinct quality of cutaneous nociception elicited by chemical or other stimuli to neuronal receptors at the superficial layers of the skin and muco-cutaneous orifices. Although recent experimental studies of the conduction and perception of itch have yielded deeper insight into the physiology of this sensory quality, little is known about the neuromechanisms involved in pruritus accompanying many inflammatory skin diseases, in particular, in atopic eczema. Previous case-control studies of our research group with patients suffering from atopic eczema (AE) revealed significantly diminished itch perception after iontophoretic application of different doses of histamine as well as substance P (i.c. injected). Further experiments using acetylcholine (ACh, i.c.) clearly demonstrated that ACh elicits pruritus instead of pain in patients with AE. The first part of the present review deals with the results of our most recent case-control studies on histamine-induced itch perception in atopics devoid of eczema as well as in patients with urticaria or psoriasis compared to atopics with or without manifest eczema. We demonstrated that both focal itch and perifocal alloknesis (i.e., itch elicited by a slight mechanical, otherwise non-itching stimulus) were significantly reduced in eczema-free atopics yet were normal in non-atopics suffering from urticaria or psoriasis. In further studies using ACh i.c. injected into the uninvolved skin of patients with AE, lichen ruber, psoriasis, type IV contact eczema, or non-specific nummular eczema (n = 10/each group), all the atopics and 6/10 psoriatics felt itch instead of burning pain, but none of the others did. Different doses of vasoactive intestinal peptide (VIP) i.c. applied to the controls and the atopics with or without eczema did not markedly increase the intensity of nociceptive sensations. However, ACh induced pain in the controls, pure pruritus in the atopics with acute eczema, and a 'mixture' of pain and itch in the atopics just free from eczema. Obviously, the quality of sensations evoked by ACh and VIP depends on the inflammatory or non-inflammatory state of the atopic skin. In a placebo-controlled, double blind study on histamine-induced focal itch and alloknesis with healthy subjects (n = 15) using naltrexone (opioid receptor antagonist) and cetirizine (H1-blocking agent), naltrexone was found to significantly reduce both itching and alloknesis. Cetirizine reduced focal itch but failed to influence the alloknesis phenomenon. The wheal and flare reaction was suppressed only by cetirizine. These different effects point to a mainly CNS-based activity of naltrexone but a peripheral level effect of cetirizine. Due to long-lasting experience with group sport as a supporting adjuvant for inpatients with AE, we evaluated, by clinical, psychometric, and physiological studies, the therapeutic efficacy of controlled physical exercise in addition to otherwise equal anti-eczematous therapy for both voluntary participants and non-participants in sports by performing several case-control studies, one followed-up to 6 months after the patients' discharge from the hospital. Regular moderate exercises neither deteriorated nor impeded the recovery from AE, ameliorated the participants' scratch controlling ability and significantly their depressed emotional mood. The non-participants failed to achieve these aims. Sweating-induced itch was inhibited in almost all participants if simple skin care (clearing by warm shower, ointment) and short-term rest were used by informed patients. In conclusion, there are several indications that itching is elicited in individuals inclined to cutaneous atopy, regardless of their eczematous or just eczema-free state, by a different physiological pathway from that in non-atopic individuals. Therefore, antipruritic agents influencing the centrally altered nociception of atopics are needed and may be expected in near future. (ABSTRACT TRUNCATED)
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PMID:Recent studies of cutaneous nociception in atopic and non-atopic subjects. 1009 77

Substance P is located in cutaneous nerve fibres and induces wheal and flare responses, accompanied by granulocyte infiltration, upon intradermal injection. Studies with animal skin and rat peritoneal mast cells have suggested that substance P induces the release of histamine and leukotriene B4 (LTB4), a potent chemoattractant for granulocytes, from skin mast cells. However, the release of LTB4 has not been detected from mast cells enzymatically isolated from human skin. In order to investigate the mechanism of granulocyte infiltration induced by substance P in human skin, we studied the release of LTB4 and histamine in response to substance P, and the effect of dexamethasone using human skin obtained from 22 nonallergic individuals. Histamine was released from all skin tissue samples in a dose-dependent manner. However, the amount of LTB4 release, both constitutive and inducible, was variable among skin preparations. Substance P induced a large release of LTB4 from the skin of eight donors (twice to six times that of the spontaneous release), but no or only negligible release from the skin of 14 donors. The amount of constitutive release of LTB4 correlated with the amount of tissue histamine. Dexamethasone selectively abolished the inducible release of LTB4, without an effect on histamine release and the constitutive release of LTB4. These results suggest that substance P induces the release of LTB4 in a certain population of human individuals by a glucocorticosteroid-dependent mechanism, and plays an important role in neurogenic inflammation with granulocyte infiltration.
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PMID:The release of leukotriene B4 from human skin in response to substance P: evidence for the functional heterogeneity of human skin mast cells among individuals. 1135 54

Skin reactivity to intradermal injections (0.1, 0.5 and 1 nM) of substance P (SP) was evaluated in 20 clinically normal dogs and 20 dogs with atopic dermatitis (AD). Saline and histamine were used as negative and positive controls, respectively. Wheal diameters were measured. Reactions were evaluated for erythema and induration and a subjective score, on a scale from 0 to 4+, was given. Evaluations were performed at 3, 5, 10, 15 and 30 min after the injections. Wheal diameters for histamine and SP injections were significantly smaller in dogs with AD compared with clinically normal dogs. In both groups, reactions to the various concentrations of SP were not significantly different from each other and were always smaller than histamine reactions. Erythema was not seen with SP injections. In addition, subjective scores for SP injections were significantly lower in dogs with AD compared with controls. The results of this study are similar to those reported in human medicine, where a role for SP in AD is proposed and desensitization of receptors to both SP and histamine is hypothesized. Further studies are needed to investigate the role of SP in the pathogenesis of canine AD.
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PMID:Intradermal skin test reactivity to histamine and substance P is blunted in dogs with atopic dermatitis. 1142 Sep 30

Senescence-accelerated mice (SAM) were established as a kind of group of related inbred strains that have been used as animal models for accelerated senescence and age-associated disorders. To analyze the characteristics of skin in SAM, the present study examined its morphology at the histological and ultrastructural levels. Histologic comparison of skin from senescence-accelerated-prone (SAM P10) and -resistant (SAM R1) mice revealed that the most characteristic features of SAM P10 were remarkable increases in the number of mast cells and in the density of collagen fibers in the dermis. Therefore, cutaneous allergic responsiveness and the proliferative activity of fibroblasts were also examined. Ultrastructurally, mast cells in the skin of SAM P10 possessed specific granules which exhibited considerable heterogeneity in electron density and various degrees of degranulation. In contrast, mast cells in the skin of control SAM R1 possessed a population of stable granules. Mast cell granules were frequently in contact with fibroblasts and were in close apposition to collagen fibers in the dermis of SAM P10. The collagen bundles were disorganized, and various diameters of collagen fibers were observed. SAM P10 demonstrated a significantly reduced wheal-and-flare reaction to histamine and tachykinins such as substance P, which suggests that skin aging may cause reduced sensitivity of mast cells and/or blood vessels to extrinsic stimuli. An in-vitro study using organ and monolayer culture demonstrated that the proliferative capacity of fibroblasts in the skin of SAM P10 was reduced in comparison with SAM R1. This is the first report that demonstrates the detailed morphological characteristics of skin in SAM P10. The findings obtained suggest that SAM P10 is a useful animal model of aged human skin, because of its many similar morphological features, including the reduction of the cutaneous allergic response, represented by neurogenic inflammation via the axon reflex, and its decreased fibroblast proliferation.
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PMID:Morphological analysis of skin in senescence-accelerated mouse P10. 1211 5

The effect of starvation on allergen-induced skin wheal responses and plasma neuropeptide levels was not previously reported. Starvation for 24 h reduces allergen-induced skin wheal responses and plasma levels of substance P and vasoactive intestinal peptide in patients with atopic eczema/dermatitis syndrome, but not in control subjects. These results may have implications for the pathophysiology of the atopic eczema/dermatitis syndrome.
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PMID:Starvation reduces allergen-induced skin wheal responses and plasma substance P and vasoactive intestinal peptide in patients with atopic eczema/dermatitis syndrome. 1240 28

Microwave radiation from mobile phones enhanced skin wheal responses induced by house dust mite and Japanese cedar pollen while it had no effect on wheal responses induced by histamine in patients with atopic eczema/dermatitis syndrome (AEDS). Microwave radiation also increased plasma levels of substance P (SP) and vasoactive intestinal peptide (VIP) in patients with AEDS. These results indicate that microwave radiation from mobile phones may enhance allergen-induced wheal responses in association with the release of SP and VIP. This finding may be useful in elucidating the pathophysiology and treatment of AEDS.
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PMID:Enhancement of allergic skin wheal responses by microwave radiation from mobile phones in patients with atopic eczema/dermatitis syndrome. 1248 40

Computer-induced stress enhanced allergen-specific skin wheal responses in patients with atopic dermatitis (AD) while it failed to do so in patients with allergic rhinitis (AR). Computer-induced stress also enhanced plasma levels of substance P (SP) and vasoactive intestinal peptide (VIP) in patients with AD, but not with AR. Peripheral blood mononuclear cells stimulated with combination of IL-4, IL-10, anti-CD40 mAb, and allergen produced allergen-specific IgE production in both patients with AD and AR. Computer-induced stress enhanced allergen-specific IgE production by peripheral blood mononuclear cells from patients with AD, but not from patients with AR. This is the first report that computer-induced stress enhances allergen-specific responses with concomitant increase of plasma levels of SP and VIP specifically in patients with AD. Since AD is often aggravated by stress, these finding may have implications for the pathophysiology and treatment of AD.
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PMID:Enhancement of allergic skin wheal responses and in vitro allergen-specific IgE production by computer-induced stress in patients with atopic dermatitis. 1267 75


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