Red hot pepper, in the science of botany is a plant belonging to the Solanaceae family and known as Capsicum annuum. Capsaicin is the active ingredient in cayenne pepper. Mast cells are cells with intracytoplasmic granules in the connective tissue, showing metachromasia under appropriate conditions. The aim of the study is to observe mast cell localization and tryptase and chymase expression in ovaries of rats administered subcutaneous capsaicin at 1 mg / kg dose during postnatal development periods. Sixty female Spraque-Dawley rats (21 d old) were used.  The rats were randomly divided into 3 groups (n=20 each) as pubertal, post pubertal and adult.  Each group was subdivided into two groups.  The first subgroup (control) was given no injections.  The second subgroup (experiment) received subcutaneous injection of equal volume of capsaicin (1 mg/kg/d) for 7 weeks. Mast cells were observed in the cortex and medulla regions of the ovary during three different developmental periods, giving rise to tryptase and chymase positive reactions. In conclusion, low dose long-term capsaicin administration does not inactivate the presence of mast cells in the ovarian tissue, and the observation of fewer tryptase and chymase immunoreactive cells in the capsaicin-treated experimental groups led us to the conclusion that capsaicin positively affected mast cell heterogeneity in gonads.

The current study, we investigated the effect of capsaicin alone or combined with metformin on induced polycystic ovary syndrome in rat adult females. The total number of animals was used (70). The study was divided into two experiments: The first experiment was to induce polycystic ovary syndrome in (50) animals were divided as follows: GI (n= 10) (CMC) served as a control group. The reminder (n = 40) GII were given Letrozole 1 mg\kg. The duration of this experiment continued (21 day). At the end of experiment, (n=10) females that received letrozole were scarified and considered as (PCOS subgroup). The GI (n=10) CMC were also scarified to ensured PCOS accrued. For histochemical analysis, the ovaries of female rats were isolated and fixed in a formalin solution 10%. In a second experiment, the reminder of female rats from first experiments GII (PCOS group n=30) divided into three subgroups (10 animals/subgroup: (Capsaicin + letrozole) subgroup, was given 0.5 mg/kg of capsaicin, (metformin) subgroup was given metformin 9 mg\ kg and (metformin + capsaicin + letrozole) subgroup. The remainder of the total number of animals studied (n = 20) (PCOS not induced) were divided into (10 animals/subgroup) (alcohol subgroup) as control group that was given 0.5 ml from alcohol and (capsaicin) without induction of polycystic ovary syndrome as a positive control subgroup, was given capsaicin (0.5 mg/ kg). The second experiment continued for 21-days after the end of the experiment. All animals were sacrificed and the ovaries were removed, fixed (10% buffered formalin), and prepared for histochemical study using Mallory's trichrome stain. The study, we recorded multiple cysts, bleeding and mucin in the PCOS subgroup compared with the CMC group. Histochemical examinations of the treated subgroups with capsaicin alone or with metformin showed an improvement in ovarian tissue, disappearance of cysts and bleeding compared with the control groups and the PCOS subgroup. We thought that capsaicin alone or in combination with metformin showed an improvement in ovarian tissue. 

A useful approach for evaluating antitussive drugs in humans is to determine the sensitivity of the cough reflex to a standard challenge. The purpose of this study was to determine if methods used to induce coughing in humans would be effective when used on awake, untrained, healthy dogs for future application in therapeutic trials involving dogs with spontaneous disease. Methods tested were: mechanically stimulating the trachea by digital compression as well as by vibration from an electric shaver, neck massager, and palm sander (11 dogs), and administering nebulized irritant (3000 micromolar capsaicin), acidic (1 M citric acid), and hypotonic (deionized water) solutions using face masks (4 dogs). The threshold for success was defined as induction of at least 2 moderate or strong coughs in at least 75% of the dogs. None of the methods tested was successful. Digital compression induced soft (n = 2) or moderate (n = 1) coughing in 3 of 11 dogs tested. Nebulization of citric acid induced 1 soft cough in 1 of 4 dogs. It was concluded that coughing cannot be successfully induced in awake, healthy dogs using methods that are successful in humans. Other strategies must be developed so that cough sensitivity can be objectively and non-invasively measured in dogs for clinical research purposes.

Objective—To compare responses of equine digital arteries (EDAs) and veins (EDVs) to human-acalcitonin gene-related peptide (hαCGRP), evaluate effect of the endothelium, and characterize receptors and sources of endogenous CGRP. Sample—Palmar digital vessels (5 to 9/experiment) from healthy adult horses killed at an abattoir. Procedures—Vessel rings were mounted under tension in organ baths containing Krebs-Henseleit solution at 30°C, with relaxation responses examined in vessels preconstricted with a thromboxane-mimetic (3 × 10(−8)M). Responses of endothelium-intact (+e) and -denuded (−e) EDAs and EDVs to hαCGRP C10−10 to 3 × 10(−7)M) were compared. Following incubation with an hαCGRP receptor antagonist (hαCGRP8–37; 1μM), responses of EDA(−e) and EDV(−e) to hαCGRP (10(−7)M) were obtained. Responses of endothelium-intact and -denuded arteries and veins to hαCGRP (3 × 10(−7)M) or capsaicin (10(−5)M) were evaluated as well as responses of endothelium-intact and -denuded EDA and EDV to hαCGRP (10(−10) to 10(−6)M) after incubation with endothelin-1 (ET-1; 10(−12)M). Results—hαCGRP resulted in nonendothelium, concentration-dependent relaxation in EDAs and EDVs, with greater responses in EDAs. Treatment with hαCGRP8–37 had minimal effect on responses to hαCGRP in either vessel type. Capsaicin induced relaxation in both vessel types. There were no differences between responses to hαCGRP for vessels pretreated with ET-1 or vehicle. Conclusions and Clinical Relevance—Both hαCGRP and capsaicin induced digital vasodilation unaffected by a functional endothelium. This suggested that endogenous CGRP likely emanates from sensory-motor nerves and may contribute to digital vasodilation.