Capsaicin

The purpose of this study was to determine whether changes occur in pulpal blood flow when capsaicin is applied to the adjacent gingival or alveolar mucosa in human beings. Laser Doppler flowmetry was used to measure changes in pulpal blood flow (PBF) after applying capsaicin to adjacent gingival mucosa in 20 human volunteers. The procedure was repeated on 10 subjects after administration of an ipsilateral inferior alveolar nerve block and on the other 10 subjects after application of topical anesthetic to their adjacent gingival and alveolar mucosa. PBF increased in 16 subjects and did not change in 4 subjects after capsaicin application. Ipsilateral inferior alveolar nerve block did not alter this effect. Pretreatment with topical lidocaine resulted in no change or decreased PBF in 8 subjects and increased PBF in 2 subjects. Changes occur in the PBF of the mandibular canine teeth of some humans when capsaicin is applied to the adjacent gingival or alveolar mucosa.

We analyze the relationship between spicy food eating and endogenous testosterone. • Testosterone is related with the quantity of hot sauce participants consumed. • No correlation was observed between testosterone and a control substance. a b s t r a c t In the present study, we analyzed the relationship between eating behavior of spicy food and endogenous testos-terone. Participants included 114 males between the ages of 18 and 44 recruited from the community. They were asked to indicate their preferences regarding spicy food and were then asked to season a sample of mashed potatoes with pepper sauce and salt (control substance) prior to evaluating the spiciness of the meal. A positive correlation was observed between endogenous salivary testosterone and the quantity of hot sauce individuals voluntarily and spontaneously consumed with a meal served as part of a laboratory task. In contrast, significant correlations were not observed between testosterone and behavioral preference for salty foods. This study suggests that behavioral preference for spicy food among men is related to endogenous testosterone levels.

It was reported in a recent study that, like capsaicin, menthol is capable of producing a desensitization to sensory irritation in the oral cavity. Whereas capsaicin is known to be able to cross-desensitize with other chemical irritants, no such information exists for menthol. To address this question, the first experiment was designed to reveal whether cross-desensitization would occur between menthol and capsaicin. After a pretest on the tongue tip in which subjects rated the intensity of irritation and cold produced by 3.5 ppm capsaicin or 0.3% l-menthol, five samples of the same stimuli were sipped and swished at 1-min intervals for 5 min. Fifteen minutes later subjects were tested on the tongue tip with either capsaicin or menthol. The results 1) confirmed self-desensitization for both chemicals, 2) demonstrated cross-desensitization of menthol by capsaicin, and 3) revealed cross-sensitization of capsaicin by menthol. This series of outcomes suggests that menthol produces much ...

Chronic pain affects quality of life and adversely affects functional outcomes. Chronic postoperative pain is a frustrating problem for the surgeon because it ruins a technically perfect procedure, and the surgeon may be unsure of treatment strategies. There is much information on chronic pain and its treatment, but it is often published outside of surgery and diffusion of this information across disciplines is slow. This article synthesizes some of this literature and provides a systematic presentation of the evidence on pain associated with peripheral nerve injury. It highlights the use of perioperative and early intervention to decrease this debilitating problem.

Approximately 20% of the adult population suffer from chronic pain that is not adequately treated by current therapies, highlighting a great need for improved treatment options. To develop effective analgesics, experimental human and animal models of pain are critical. Topically/intra-dermally applied capsaicin induces hyperalgesia and allodynia to thermal and tactile stimuli that mimics chronic pain and is a useful translation from preclinical research to clinical investigation. Many behavioral and self-report studies of pain have exploited the use of the capsaicin pain model, but objective biomarker correlates of the capsaicin augmented nociceptive response in nonhuman primates remains to be explored. Here we establish an aversive capsaicin-induced fMRI model using non-noxious heat stimuli in Cynomolgus monkeys (n = 8). BOLD fMRI data were collected during thermal challenge (ON:20 s/42°C; OFF:40 s/35°C, 4-cycle) at baseline and 30 min post-capsaicin (0.1 mg, topical, forearm) appl...

The transient receptor potential vanilloid subfamily 1 (TRPV1) is an ion channel activated by capsaicin, heat, protons and endogenous ligands such as anandamide. It is largely expressed in the urinary tract of mammals. Structures in which the receptor expression is firmly established include sensory fibers and urothelial cells, although the presence of TRPV1 in other cell types has been reported. As in other systems, pain perception was the first role attributed to TRPV1 in the urinary tract. However, it is now increasingly clear that TRPV1 also regulates the frequency of bladder reflex contractions, either through direct excitation of sensory fibers or through urothelial-sensory fiber cross talk involving the release of neuromediators from the epithelial cells. In addition, the recent identification of the receptor in urothelial and prostatic cancer cells raise the exciting hypothesis that TRPV1 is involved in cell differentiation. Desensitization of the receptor by capsaicin and resiniferatoxin has been investigated for therapeutic purposes. For the moment, lower urinary tract dysfunctions in which some benefit was obtained include painful bladder syndrome and overactive bladder of neurogenic and non-neurogenic origin. However, desensitization may become obsolete when non-toxic, potent TRPV1 antagonists become available.

Background:  Mechanisms underlying cough and bronchoconstriction in patients with cough-variant asthma (CVA) are not well established. Differences in location or degree of activation of eosinophils and allergic cytokines have been suggested as the likely causes. To address this issue, we have carried out a comparative study of airway inflammatory markers between patients with CVA and classic asthma (CA). The relationship between these markers with airway hyperresponsiveness (AHR) and cough sensitivity has also been studied.Methods:  Twenty-seven non-smokers and steroid-naive patients with CVA (12) and CA (15) were examined. Capsaicin challenge, histamine bronchoprovocation test, nitric oxide levels in exhaled air and sputum induction were performed in all of them. Differential cell sputum recount and supernatant concentrations of eosinophil granule-derived cationic proteins (ECP), interleukin (IL)5, IL8 and tumour necrosis factor (TNF)-α were also measured.Results:  There were no significant differences in either the inflammatory pattern of soluble markers or differential cell counts between CA and CVA. Histamine PC20 was correlated with IL-5 in CVA, whereas it was associated with sputum eosinophilia in CA. Cough sensitivity (log C5) and histamine PC20 were inversely related in CA.Conclusions:  Although the pattern of inflammatory sputum markers in patients with asthma and cough-variant asthma is similar, its relation with bronchial hyperreactivity and cough sensitivity is different in each group.

To validate the potential anti-inflammatory and analgesic role of sita- and vildagliptin, five different experimental models were used in mice: i) mustard oil-induced ear edema, ii) neutrophil accumulation, iii) mechanical and iv) thermal touch sensitivity in complete Freund's adjuvant-induced arthritis and v) capsaicin-induced plasma extravasation in the urinary bladder. For the complete examination period in i) the dose of 10mg sitagliptin as well as 1-10mg vildagliptin was found to significantly decrease ear edema as compared to positive control (p<0.05, n=8/group). All doses of sitagliptin provided an anti-inflammatory effect p<0.005 (n=10/group) in test ii) and an analgesic effect in iii) except 3mg. Vildagliptin was similarly effective in test ii) (p<0.005, n=10/group) as sitagliptin, but it failed to affect mechanical touch sensitivity. Unlike mechanical touch sensitivity, both gliptins could beneficially act on the thermal threshold (p<0.05, n=10/group). And only in tests v) could both gliptins reverse inflammation. Further studies are needed to support the suggestion that the utilization of these beneficial effects of gliptins may be considered in the treatment of Type 2 diabetic patients.

Curatella americana L. (Dilleneaceae) popularly known as ‘cajueiro-bravo’ and ‘sambaı́ba’ is used in Brazilian folk medicine for the treatment of inflammation and ulcer. The anti-inflammatory and analgesic tests were conducted with the hydroalcoholic extract (HAE) of the bark of the plant. The HAE inhibited mouse ear oedema induced by o-tetradecanoyl phorbol acetate (TPA) and by capsaicin. While the ID50 values obtained for the HAE against these two irritants were 40.8±1.7 and 30±1.2 mg/kg i.p. (mean±S.E.M., n=6), respectively, the corresponding value for carrageenan induced paw oedema (3 h) was 21.8±2.1 mg/kg, i.p., n=6. In the established adjuvant-induced arthritis model, the HAE significantly inhibited the oedema in daily doses of 50 mg/kg, i.p. (n=10). The HAE also inhibited acetic acid-induced writhing (ID50 23.2±0.8 mg/kg, i.p., n=6) and the formalin-induced late phase paw licking response (ID50 11.9±1.2 mg/kg, i.p., n=10) in the mice. However, the HAE was inactive in the formalin-induced initial paw licking response in mice or heat induced tail flick response in rats. The HAE has shown both anti-inflammatory and peripheral analgesic activities when administrated in the mouse by the intraperitoneal route in doses which are at least 12 times lower than its LD50 dose of 647 mg/kg, i.p.

Pungent sensation of hot peppers is thought to be mediated by vanilloid receptor subtype-1 (VR1), which can be activated by capsaicin, but there is little information regarding its histological localization in the tongue. We examined the immunohistochemical distribution of VR1 in the rat tongue. Intensely labeled VR1-immunoreactive (VR1-IR) fibers were concentrated in the circumvallate, foliate, and fungiform papillae, while sparse