Animals ; Rats ; Neuroprotective Agents/pharmacology* ; Amyloid beta-Peptides ; PC12 Cells ; Polyunsaturated Alkamides/pharmacology* ; Apoptosis ; Cell Survival ; Peptide Fragments

Capsaicin is a lipid-soluble vanillin alkaloid extracted from Capsicum plants in the Solanaceae family, which is the main active ingredient in capsicum, with multiple functions such as anti-inflammation, analgesia, cardiovascular expansion, and gastric mucosa protection. Recently, capsaicin has been confirmed as a potential antitumor compound. It can induce cell cycle arrest, inhibit cancer cell proliferation, metastasis, invasion, and angiogenesis, and promote apoptosis or autophagy in malignancy cell models and animal models of lung cancer, breast cancer, gastric cancer, and liver cancer. Meanwhile, capsaicin shows a synergistic antitumor effect when combined with other antitumor drugs such as sorafenib. Based on the recent literature on the antitumor effect of capsaicin, the present study analyzed the molecular mechanism of capsaicin in resisting tumors by inducing apoptosis and reviewed the effects of capsaicin in inducing tumor cell cycle arrest, inhibiting tumor cell proliferation, metastasis, and angiogenesis, and combating tumors with other drugs, thereby providing a theoretical basis for further research of capsaicin and its rational development and utilization.
Animals ; Antineoplastic Agents/therapeutic use* ; Apoptosis ; Capsaicin/therapeutic use* ; Capsicum ; Cell Line, Tumor ; Cell Proliferation ; Liver Neoplasms

This study aims to explore the effect of Jinzhen Oral Liquid(JOL) on cough after infection in rats and the mechanism. To be specific, a total of 60 male SD rats were classified into 6 groups: normal group(equivalent volume of distilled water, ig), model group(equivalent volume of distilled water, ig), Dextromethorphan Hydrobromide Oral Solution group(3.67 mL·kg~(-1), ig), high-, medium-, and low-dose JOL groups(11.34, 5.67, and 2.84 mL·kg~(-1), respectively, ig). Lipopolysaccharide(LPS, nasal drip), smoking, and capsaicin(nebulization) were employed to induce cough after infection in rats except the normal group. Administration began on the 19 th day and lasted 7 days. Capsaicin(nebulization) was used to stimulate cough 1 h after the last administration and the cough frequency and cough incubation period in rats were recorded. The pathological morphology of lung tissue was observed based on hematoxylin-eosin(HE) staining. Immunohistochemistry(IHC) was used to detect the specific expression of transient receptor potential vanilloid 1(Trpv1), nerve growth factor(NGF), tropomyosin receptor kinase A(TrkA), and phosphorylated-p38 mitogen-activated protein kinase(p-p38 MAPK) in lung tissue, Western blot the protein expression of Trpv1, NGF, TrkA, and p-p38 MAPK in lung tissue, and real-time fluorescent quantitative polymerase chain reaction(real-time PCR) the mRNA expression of Trpv1, NGF, and TrkA. The results showed that model group demonstrated significantly high cough frequency, obvious proliferation and inflammatory cell infiltration in lung tissue, significantly enhanced positive protein expression of Trpv1, NGF, TrkA, and p-p38 MAPK in lung tissue and significant increase in the mRNA expression of Trpv1, NGF, and TrkA compared with the normal group. Compared with the model group, JOL can significantly reduce the cough frequency, alleviate the pathological changes of lung tissue, and decrease the protein expression of Trpv1, NGF, TrkA, and p-p38 MAPK in lung tissue, and high-dose and medium-dose JOL can significantly lower the mRNA expression of Trpv1, NGF, and TrkA. This study revealed that JOL can effectively inhibit Trpv1 pathway-related proteins and improve cough after infection. The mechanism is that it reduces the expression of NGF, TrkA, and p-p38 MAPK in lung tissue, thereby decreasing the expression of Trpv1 and cough sensitivity.
Animals ; Capsaicin/adverse effects* ; Cough/drug therapy* ; Dextromethorphan/adverse effects* ; Eosine Yellowish-(YS)/adverse effects* ; Hematoxylin ; Lipopolysaccharides/adverse effects* ; Male ; Medicine, Chinese Traditional ; Nerve Growth Factor/metabolism* ; RNA, Messenger ; Rats ; Rats, Sprague-Dawley ; Receptor, trkA/metabolism* ; TRPV Cation Channels/metabolism* ; Tropomyosin/metabolism* ; Water/metabolism* ; p38 Mitogen-Activated Protein Kinases/metabolism*

This article is to investigate the effect of piperine on the small intestine of mice with Parkinson's disease with dementia(PDD). Ninety-six C57 BL/6 mice of SPF grade were randomly divided into 8 groups(male, 12 in each group): normal group, model group, autophagy inhibitor group(6-amino-3-methylpurine, 3 MA, 30 mg·kg~(-1)), autophagy activator group(rapamycin, 1 mg·kg~(-1)), low, medium, and high dose piperine groups(10, 20, 40 mg·kg~(-1)), and medopar group(112.5 mg·kg~(-1)). Except for the normal group, mice in each group were injected subcutaneously with reserpine(0.1 mg·kg~(-1)) once every 48 hours for 40 days. In addition, on the 20 th day of administration, except for the normal group, the mice in the other groups were subjected to bilateral common carotid artery occlusion to finally prepare PDD models. At the same time, each group was given the corresponding drug treatment once a day for 40 days. After the last administration, the behavioral changes of mice were observed by autonomic activity experiment and hot plate experiment. The expression levels of α-synuclein(α-syn) and tyrosine hydroxylase(TH) in the small intestine were detected by immunohistochemistry. The expression levels of beclin-1, microtubule-associated protein 1 light chain 3 B(LC3 B) and p62 in the small intestine were detected by immunofluorescence assay. Hematoxylin-eosin staining was used to observe the pathological morphology of small intestine tissues in each group. Enzyme-linked immunosorbent assay was adopted for detection of β-amyloid precursor protein(APP), p-tau, acetylcholine transferase(ChAT), interleukin-6(IL-6) and tumor necrosis factor-α(TNF-α) in small intestine. Real-time fluorescent quantitative polymerase chain reaction was used to detect the expression of α-syn, TH, beclin-1, microtubule-associated protein 1 light chain 3(LC3), and p62 mRNA and mmu-miR-99 a-5 p in the small intestine. The results of this study showed that, as compared with the model group, the number of activities, the expression levels of ChAT, TH, and p62 were significantly increased in the 3 MA group, the various piperine dose groups, and the medopar group(P<0.05), and their first foot licking time was shortened; APP, p-tau, IL-6, TNF-α, α-syn, beclin-1, LC3 B and mmu-miR-99 a-5 p expression levels were significantly reduced(P<0.05). However, as compared with the model group, the number of activities, ChAT, TH, and p62 expression levels in the rapamycin group were significantly reduced(P<0.05), and the APP, p-tau, IL-6, TNF-α, α-syn, beclin-1, LC3 B and mmu-miR-99 a-5 p expression levels were significantly increased(P<0.05). As compared with the 3 MA group, the number of activities, ChAT, TH, and p62 expression levels were significantly reduced in the low and medium dose piperine groups and rapamycin group(P<0.05); howe-ver, their first foot licking time was significantly prolonged, APP, p-tau, IL-6, TNF-α, α-syn, beclin-1, LC3 B and mmu-miR-99 a-5 p expression levels were increased significantly(P<0.05). As compared with the medopar group, the number of activities, ChAT, TH, and p62 expression levels were significantly reduced in low dose piperine group and rapamycin group(P<0.05), but their first foot licking time was significantly extended, and APP, p-tau, IL-6, TNF-α, α-syn, beclin-1, LC3 B and mmu-miR-99 a-5 p expression levels were significantly increased(P<0.05). In addition, as compared with the normal group, the small intestinal epithelial cells of the model group and the rapamycin group were shed off a lot, with severe damages of intestinal mucosa as well as edema and shedding of the small intestine villi. After administration of the therapeutic interventions, the small intestinal epithelial cells of the 3 MA group, each dose group of piperine, and the medopa group were slightly damaged and the villi were slightly shed off. In summary, piperine has a protective effect on the small intestine of PDD model mice, showing reduced expression of mmu-miR-99 a-5 p, pro-inflammatory factors and autophagy factors, and the mechanism of slowing PDD pathological symptoms may be related to the inhibition of autophagy.
Alkaloids ; Animals ; Autophagy ; Benzodioxoles ; Dementia ; Intestine, Small ; Male ; Mice ; Parkinson Disease ; Piperidines ; Polyunsaturated Alkamides

PURPOSE: An older female predominance has been reported among chronic cough patients in Western countries, which is considered to be associated with a higher cough sensitivity in females. However, the characteristics of Chinese chronic cough patients remain unclear. This study aimed to explore the age and sex distribution as well as their relationship with cough reflex sensitivity to capsaicin in Chinese chronic cough patients. METHODS: We analyzed the demographic features of 1,882 consecutive chronic cough patients who attended our cough clinic in Guangzhou, China. Cough sensitivity to capsaicin, which was defined as the lowest concentration of capsaicin causing 5 coughs or more (C5), was measured in 539 of the 1,882 patients and 68 healthy volunteers. RESULTS: The mean age of the patients was 43.0 ± 13.7 years and patients aged <50 years accounted for more than two-thirds of the study population. Around 87% of the patients were never-smokers. The proportion of females (51.5%) was almost equal to that of males (48.5%). The pattern of the age and sex distribution was consistently reflected within most common causes of chronic cough, while a female predominance was shown in patients with cough-variant asthma and patients aged ≥50 years. Female patients had higher cough sensitivity to capsaicin than male patients (log C5: 1.58 ± 0.84 vs. 2.04 ± 0.84 μmol/L, P = 0.001), and patients aged ≥50 years had higher cough sensitivity to capsaicin than patients aged <50 years. CONCLUSIONS: In China, patients with chronic cough have a roughly equal sex distribution and a middle-aged predominance, irrespective of a higher cough sensitivity to capsaicin in females and older patients. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02591550
Age Distribution ; Asian Continental Ancestry Group ; Asthma ; Capsaicin ; China ; Cough ; Female ; Healthy Volunteers ; Humans ; Male ; Reflex ; Sex Distribution

The capsaicin receptor TRPV1 (transient receptor potential vanilloid 1) has been an object of intense interest for pharmacological development on account of its critical role in nociception. In the course of structure activity analysis, it has become apparent that TRPV1 ligands may vary dramatically in the rates at which they interact with TRPV1, presumably reflecting differences in their abilities to penetrate into the cell. Using a fast penetrating agonist together with an excess of a slower penetrating antagonist, we find that we can induce an agonist response of limited duration and, moreover, the duration of the agonist response remains largely independent of the absolute dose of agonist, as long as the ratio of antagonist to agonist is held constant. This general approach for limiting agonist duration under conditions in which absolute agonist dose is variable should have more general applicability.
Capsaicin ; Ligands ; Nociception

Transient receptor potential vanilloid subtype 1 (TRPV1) on astrocytes prevents ongoing degeneration of nigrostriatal dopamine (DA) neurons in MPP⁺-lesioned rats via ciliary neurotrophic factor (CNTF). The present study determined whether such a beneficial effect of astrocytic TRPV1 could be achieved after completion of injury of DA neurons, rather than ongoing injury, which seems more relevant to therapeutics. To test this, the MPP⁺-lesioned rat model utilized here exhibited approximately 70~80% degeneration of nigrostriatal DA neurons that was completed at 2 weeks post medial forebrain bundle injection of MPP⁺. TRPV1 agonist, capsaicin (CAP), was intraperitoneally administered. CNTF receptor alpha neutralizing antibody (CNTFRαNAb) was nigral injected to evaluate the role of CNTF endogenously produced by astrocyte through TRPV1 activation on DA neurons. Delayed treatment of CAP produced a significant reduction in amphetamine-induced rotational asymmetry. Accompanying this behavioral recovery, CAP treatment increased CNTF levels and tyrosine hydroxylase (TH) activity in the substantia nigra pars compacta (SNpc), and levels of DA and its metabolites in the striatum compared to controls. Interestingly, behavioral recovery and increases in biochemical indices were not reflected in trophic changes of the DA system. Instead, behavioral recovery was temporal and dependent on the continuous presence of CAP treatment. The results suggest that delayed treatment of CAP increases nigral TH enzyme activity and striatal levels of DA and its metabolites by CNTF endogenously derived from CAP-activated astrocytes through TRPV1, leading to functional recovery. Consequently, these findings may be useful in the treatment of DA imbalances associated with Parkinson's disease.
Animals ; Antibodies, Neutralizing ; Astrocytes ; Capsaicin ; Ciliary Neurotrophic Factor ; Dopamine ; Dopaminergic Neurons ; Medial Forebrain Bundle ; Models, Animal ; Neurons ; Parkinson Disease ; Pars Compacta ; Rats ; Receptor, Ciliary Neurotrophic Factor ; Tyrosine 3-Monooxygenase

BACKGROUND: The trigeminal nucleus caudalis (Vc) is a primary central site for trigeminal transmitting. Noxious stimulation of the trigeminal nociceptors alters the central synaptic releases and neural expression of some inflammatory and trophic agents. Orexin-A and the orexin 1 receptor (OX1R) are expressed in pain pathways including trigeminal pain transmission. However, the the mechanism(s) underling orexin-A effects on trigeminal pain modulation have not been fully clarified. METHODS: Trigeminal pain was induced by subcutaneous injection of capsaicin in the upper lip in rats. The effect of trigeminal pain on cyclooxygenase-2 (COX-2) and brain-derived neurotrophic factor (BDNF) expression in the Vc of animals was determined by immunofluorescence. Subsequently, OX1R agonist (orexin-A) and antagonist (SB-334867-A) was administrated in the Vc to investigate the possible roles of the Vc OX1R on changes in COX-2 and BDNF levels following pain induction. RESULTS: The data indicated an increase in COX-2 and decrease in BDNF immuno-reactivity in the Vc of capsaicin, and capsaicin- pretreated with SB-334867-A (80 nM), groups of rat. However, the effect of capsaicin on COX-2 and BDNF expressions was reversed by a Vc microinjection of orexin-A (100 pM). CONCLUSIONS: Overall, the present data reveals that orexin-A can attenuate capsaicin-induced trigeminal pain through the modulation of pain effects on COX-2 and BDNF expressions in the Vc of rats.
Animals ; Brain-Derived Neurotrophic Factor ; Capsaicin ; Cyclooxygenase 2 ; Facial Pain ; Fluorescent Antibody Technique ; Injections, Subcutaneous ; Lip ; Microinjections ; Nociceptors ; Orexin Receptor Antagonists ; Orexins ; Pain Measurement ; Pain Perception ; Rats ; Trigeminal Caudal Nucleus ; Trigeminal Neuralgia ; Trigeminal Nuclei

Chronic postsurgical pain (CPSP) is an unwanted adverse event in any operation. It leads to functional limitations and psychological trauma for patients, and leaves the operative team with feelings of failure and humiliation. Therefore, it is crucial that preventive strategies for CPSP are considered in high-risk operations. Various techniques have been implemented to reduce the risk with variable success. Identifying the risk factors for each patient and applying a timely preventive strategy may help patients avoid the distress of chronic pain. The preventive strategies include modification of the surgical technique, good pain control throughout the perioperative period, and preoperative psychological intervention focusing on the psychosocial and cognitive risk factors. Appropriate management of CPSP patients is also necessary to reduce their suffering. CPSP usually has a neuropathic pain component; therefore, the current recommendations are based on data on chronic neuropathic pain. Hence, voltage-dependent calcium channel antagonists, antidepressants, topical lidocaine and topical capsaicin are the main pharmacological treatments. Paracetamol, NSAIDs and weak opioids can be used according to symptom severity, but strong opioids should be used with great caution and are not recommended. Other drugs that may be helpful are ketamine, clonidine, and intravenous lidocaine infusion. For patients with failed pharmacological treatment, consideration should be given to pain interventions; examples include transcutaneous electrical nerve stimulation, botulinum toxin injections, pulsed radiofrequency, nerve blocks, nerve ablation, neuromodulation and surgical management. Physical therapy, cognitive behavioral therapy and lifestyle modifications are also useful for relieving the pain and distress experienced by CPSP patients.
Acetaminophen ; Analgesics, Opioid ; Anti-Inflammatory Agents, Non-Steroidal ; Antidepressive Agents ; Botulinum Toxins ; Calcium Channel Blockers ; Capsaicin ; Chronic Pain ; Clonidine ; Cognitive Therapy ; Drug Therapy ; Humans ; Incidence ; Ketamine ; Lidocaine ; Life Style ; Nerve Block ; Neuralgia ; Pain Management ; Pain, Intractable ; Pain, Postoperative ; Perioperative Period ; Physical Therapy Modalities ; Psychological Trauma ; Risk Factors ; Surgical Procedures, Operative ; Transcutaneous Electric Nerve Stimulation

Postherpetic neuralgia (PHN) is the most troublesome side effect of Herpes Zoster (HZ), which mainly affects the elderly and immunocompromised populations. Despite the current advancement of treatments, PHN persists in many individuals influencing their daily activities and reducing their quality of life. Anticonvulsants, antidepressants, topical therapies including lidocaine and capsaicin, and opioids, are the most widely used therapies for the treatment of PHN. These medications come with their adverse effects, so they should be used carefully with the elderly or with patients with significant comorbidities. Other measures like botulinum toxin, nerve blocks, spinal cord stimulation, and radiofrequency have also contributed significantly to the management of PHN. However, the efficacy, safety, and tolerability of these invasive methods need to be carefully monitored when administering them. Early diagnosis and early initiation of treatment can reduce the burden associated with PHN. The zoster vaccine has effectively reduced the incidence of HZ and PHN. In this article, we discuss the treatment options available for the management of PHN, mainly focusing on the efficacy and safety of different therapeutic modalities.
Aged ; Analgesics, Opioid ; Anticonvulsants ; Antidepressive Agents ; Botulinum Toxins ; Capsaicin ; Comorbidity ; Early Diagnosis ; Herpes Zoster ; Herpes Zoster Vaccine ; Humans ; Incidence ; Lidocaine ; Nerve Block ; Neuralgia, Postherpetic ; Quality of Life ; Spinal Cord Stimulation