Capsaicin, The Vanilloid Receptor TRPV1 Agonist in Neuroprotection: Mechanisms Involved and Significance.

Hot peppers, also called chilli, chilli pepper, or paprika of the plant genus Capsicum (family Solanaceae), are one of the most used vegetables and spices worldwide. Capsaicin (8-methyl N-vanillyl-6-noneamide) is the main pungent principle of hot green and red peppers. By acting on the capsaicin receptor or transient receptor potential cation channel vanilloid subfamily member 1 (TRPV1), capsaicin selectively stimulates and in high doses defunctionalizes capsaicin-sensitive chemonociceptors with C and Aδ afferent fibers. This channel, which is involved in a wide range of neuronal processes, is expressed in peripheral and central branches of capsaicin-sensitive nociceptive neurons, sensory ganglia, the spinal cord, and different brain regions in neuronal cell bodies, dendrites, astrocytes, and pericytes. Several experimental and clinical studies provided evidence that capsaicin protected against ischaemic or excitotoxic cerebral neuronal injury and may lower the risk of cerebral stroke. By preventing neuronal death, memory impairment and inhibiting the amyloidogenic process, capsaicin may also be beneficial in neurodegenerative disorders such as Parkinson's or Alzheimer's diseases. Capsaicin given in systemic inflammation/sepsis exerted beneficial antioxidant and anti-inflammatory effects while defunctionalization of capsaicin-sensitive vagal afferents has been demonstrated to increase brain oxidative stress. Capsaicin may act in the periphery via the vagal sensory fibers expressing TRPV1 receptors to reduce immune oxidative and inflammatory signalling to the brain. Capsaicin given in small doses has also been reported to inhibit the experimentally-induced epileptic seizures. The aim of this review is to provide a concise account on the most recent findings related to this topic. We attempted to delineate such mechanisms by which capsaicin exerts its neuronal protective effects. We also aimed to provide the reader with the current knowledge on the mechanism of action of capsaicin on sensory receptors.

Toxicokinetic Study of a Gastroprotective Dose of Capsaicin by HPLC-FLD Method.

BACKGROUND: A low dose of capsaicin and its natural homologs and analogs (capsaicinoids) have shown to prevent development of gastric mucosal damage of alcohol and non-steroid anti-inflammatory drugs. Based on this experimental observation, a drug development program has been initiated to develop per os applicable capsaicin containing drugs to eliminate gastrointestinal damage caused by non-steroid anti-inflammatory drugs. METHODS: As a part of this program, a sensitive and selective reverse-phase high-performance liquid chromatography-based method with fluorescence detection has been developed for quantification of capsaicin and dihydrocapsaicin in experimental dog's plasma. RESULTS: The method was evaluated for a number of validation characteristics (selectivity, repeatability, and intermediate precision, LOD, LOQ, and calibration range). The limit of detection (LOD) was 2 ng/mL and the limit of quantification (LOQ) was 10 ng/mL for both capsaicin and dihydrocapsaicin. The method was used for analysis of capsaicin and dihydrocapsaicin in the plasma samples obtained after per os administration of low doses (0.1, 0.3, and 0.9 mg/kg bw) of Capsaicin Natural (USP 29) to the experimental animals. CONCLUSIONS: The obtained results indicated that the administered capsaicinoids did not reach the general circulation.

Membrane-bound ATP-dependent Energy Systems, as Extra- and Intracellular Key Signals for Gastrointestinal Functions and their Regulations in the Gastrointestinal Mucosa.

AIMS: Our research group has carried out various biochemical examinations in rat gastric ulcer models and in human gastrointestinal resecates obtained from patient who underwent gastric intervention due to peptic ulcer disease. Biochemical methods gave excellent possibility to approach the biochemical events taking place in tissues, cellular and subcellular regulatory levels during of ulcer development and of its prevetions. This paper gives a brief summary of these biochemical examinations conducted during this study period started from the 1960's up till now. RESULTS AND CONCLUSIONS: 1. The decreased action of gastric acid secretory responses is not needed for duodenal and gastric ulcer healing in patients with peptic ulcer; 2. The surgical and chemical vagotomy resulted in various biochemical changes in the rat stomach; 3. The presence of Na+-K+-dependent ATPase and adenylate cyclase can be demostrated both in the rat and human gastric fundic mucosa; 4. The mitocondrial ATP is a common substrate for these membrane-bound ATP-dependent enzymes, and a multiple feedback mechanism existing between these two membrane-bound enzymes altered by mediators, hormones and drugs; 5. This feedback mechanism exists in the GI mucosa under different pathological conditions and during certain drug actions; 6. The development of mucosal damage and prevention depends on the actual regulatory state of above mentioned feedback mechanism between the membrane-bound ATP-dependent energy systems; 7.The drug actions depend on the actual functional state of target organ; 8. Biochemical gradients exist between the biochemical structure of the fundic, antral, duodenal and jejunal mucosa in patients with gastric hyperacidity, which is gradually downregulated by the decrease of gastric acid secretory responses, and totally disappears in patients with hypacidity; 9. No biochemically proven tissue hypoxia - around the chronic ulcer, duodenal and jejunal ulcers - exists in patients with chronic peptic ulcer; 10. The cellular and tissue protection differ from each other in the gastrointestinal tract; 11. Helicobacter pylori does not produce damage at the level of cell membrane, mitochondrion and DNA - given alone or in combination with indomethacin - on freshly isolated rat gastric mucosal cells. 12. A biochemical explanation is given to ulcer development in humans and in different animal models.

Cellular Energetical Actions of "Chemical" and "Surgical" Vagotomy in Gastrointestinal Mucosal Damage and Protection: Similarities, Differences and Significance for Brain-Gut Function.

BACKGROUND: The authors, as internists, registered significant difference in the long lasting actions of surgical and chemical (atropine treatment) vagotomy in patients with peptic ulcer during second half of the last century (efficency, gastric acid secretion, gastrointestinal side effects, briefly benefical and harmful actions were examined). AIMS: 1. Since the authors participated in the establishing of human clinical pharmacology in this field, they wanted to know more and more facts of the acute and chronic effects of surgical and chemical (atropine treatment) on the gastrointestinal mucosal biochemisms and their actions altered by bioactive compounds and scavengers regarding the development of gastric mucosal damage and protection. METHODS: The observations were carried out in animals under various experimental conditions (in intact, pylorus-ligated rats, in different experimental ulcer models, together with application of various mucosal protecting compounds) without and with surgical vagotomy and chemical vagotomy produced by atropine treatment. RESULTS: 1. No changes were obtained in the cellular energy systems (ATP, ADP, AMP, cAMP, "adenylate pool", "energy charge" [(ATP+0.5 ADP)/ (ATP+ADP+AMP)] of stomach (glandular part, forestomach) in pylorus ligated rats after surgical vagotomy in contrast to those produced by only chemical vagotomy; 2. The effects of the gastric mucosal protective compounds [atropine, cimetidine, prostaglandins, scavengers (like vitamin A, ß-carotene), capsaicin] disappeared after surgical vagotomy; 3. The extents of different chemical agents induced mucosal damaging effects were enhanced by surgical vagotomy and was not altered by chemical vagotomy; 4. The existence of feedback mechanisms of pharmacological (cellular and intracellular) regulatory mechanisms between the membrane-bound ATPdependent energy systems exists in the gastric mucosa of intact animals, and after chemical vagotomy, but not after surgical vagotomy. CONCLUSIONS: 1. Increased vagal nerve activity takes place in the gastric mucosal damage; 2 both surgical and chemical vagotomy result mucosal protective affect on the gastric mucosal in different damaging experimental models; 3. The capsaicin-induced gastric mucosal damage depends on the applied doses, presence of anatomically intact vagal nerve (but independent from the chemical vagotomy), 4. The central and pheripheral neural regulations differ during gastric mucosal damage and protection induced by drugs, bioactive compounds, scavengers.

A validated HPLC-FLD method for analysis of intestinal absorption and metabolism of capsaicin and dihydrocapsaicin in the rat.

A sensitive and selective reverse-phase high performance liquid chromatographic method with fluorescence detection has been developed for determination of capsaicin (8-methyl-N-vanillyl-(trans)-6-nonenamid) and dihydrocapsaicin (8-methyl-N-vanillylnonanamide) in samples generated in rat small intestine luminal perfusion experiments. The experiments were designed to study the biotransformation of capsaicinoids in the small intestine in the rat. The chromatographic separation was performed at room temperature on a ZORBAX Eclipse(®) XDB-C8 column using isocratic elution with a mobile phase consisting 0.05M orthophosphoric acid solution and acetonitrile (60:40, v/v; pH 3.0) with a flow rate of 1.5mL/min. Fluorescence detection was performed at excitation and emission wavelengths of 230 and 323nm, respectively. The method was evaluated for a number of validation characteristics (accuracy, repeatability and intermediate precision, limit of detection, limit of quantification and calibration range). The limit of detection (LOD) was 50ng/mL and the limit of quantification (LOQ) was 100ng/mL for both capsaicin and dihydrocapsaicin reference standards dissolved in blank perfusate. The method was successfully applied for investigation of intestinal absorption of capsaicin and dihydrocapsaicin while 30µg/mL standardized Capsicum extract - containing capsaicin and dihydrocapsaicin - was luminally perfused for a 90min period. The structure of the glucuronide metabolites of capsaicin and dihydrocapsaicin appeared in the perfusate was identified by mass spectrometry.

Capsaicin as new orally applicable gastroprotective and therapeutic drug alone or in combination with nonsteroidal anti-inflammatory drugs in healthy human subjects and in patients.

BACKGROUND: Capsaicin is a specific compound acting on capsaicin-sensitive afferent nerves. AIM: Capsaicin was used to study the different events of human gastrointestinal physiology, pathology, and clinical pharmacology, and possible therapeutic approaches to enhance gastrointestinal mucosal defense in healthy human subjects and in patients with various different gastrointestinal disorders as well as its use with nonsteroidal anti-inflammatory drugs (NSAIDs) in healthy subjects and in patients. MATERIALS AND METHODS: The observations were carried out in 198 healthy human subjects and in 178 patients with different gastrointestinal (GI) diseases (gastritis, erosions, ulcer, polyps, cancer, inflammatory bowel diseases, colorectal polyps, cancers), and in 69 patients with chronic (Helicobacter pylori positive and negative) gastritis (before and after eradication treatment). The gastric secretory responses and their chemical composition, gastric emptying, sugar loading test, gastric transmucosal potential difference (GTPD) with application of capsaicin alone, after ethanol alone and with capsaicin, indomethacin-induced gastric mucosal microbleeding without and with capsaicin were studied. The immunohistochemical examinations of the capsaicin receptor (TRVP1), calcitonin gene- related peptide (CGRP), and substance P (SP) were carried out in gastrointestinal tract, and especially in patients with chronic gastritis (with and without Helicobacter infection, before and after classical eradication treatment). Classical molecular pharmacological methods were applied to study the drugs inhibiting the gastric basal acid output. RESULTS: Capsaicin decreased the gastric basal output, enhanced the "non-parietal" (buffering) component of gastric secretory responses, and gastric emptying, and the release of glucagon. Capsaicin prevented the indomethacin- and ethanol-induced gastric mucosal damage; meanwhile capsaicin itself enhanced (GTPD). Capsaicin prevented the indomethacin-induced gastric mucosal microbleeding. The expression of TRVP1 and CGRP increased in the gastric mucosa of patients with chronic gastritis (independently of the presence of Helicobacter pylori infection), and the successfully carried out eradication treatment. The human first phase examinations (the application of acetylsalicylic acid (ASA), diclqfenac, and naproxen together with capcaicinoids) (given in doses that stimulate capsaicin-sensitive afferent vagal nerves) showed no change in the pharmacokinetic parameters of ASA and diclofenac and the ASA and diclofenac-induced platelet aggregation. CONCLUSIONS: Capsaicin represents a new orally applicable gastroprotective agent in healthy human subjects and in patients with different chemical and Helicobacter pylori-induced mucosal damage and in many other diseases requiring treatment with NSAIDs.

Role of nitric oxide in the central interferon-alpha-induced inhibition of gastric acid secretion in rats.

Cytokines are known to play a key role in regulation of gastric functions. Interferon-alpha (IFN-α) has been published to impair gastric motility. Aims of this study were to clarify effect of IFN-α on gastric acid secretion (GAS) and determine role of nitric oxide (NO) in the process. Both subcutaneous (1000, 10000, 100 000 IU, s.c.) and intracisternal (10, 100, 1000 IU, i.c.) injections of IFN-α dose-dependently inhibited GAS induced by pylorus ligation in male SD rats in 2 hrs (370±40, 233±39, 208±50 micromol vs control 415±59 micromol and 481±50, 249±75, 141±25 micromol vs control 485±65 micromol, respectively). Central doses inducing same level inhibition were 100 times lower. NOS inhibitor L-NAME (3 mg/kg, i.v.) blocked the inhibitory effect of i.c. ED(50) dose 100 IU IFN-α (507±75 micromol/2 hrs), while L-arginine, the substrate of nitric oxide synthase (NOS) prevented L-NAME action (266±82 micromol/2 hrs). D-arginine failed to prevent L-NAME action on IFN-α-induced inhibition of GAS. Aminoguanidine, a selective inhibitor of inducible NOS (iNOS) failed to block IFN-α induced inhibition of GAS. Results suggest that IFN-α inhibits GAS centrally through nitric oxide pathways probably mediated by continuous isoform of NOS that can be important in regulation of GAS in healthy or pathological conditions.

Molecular pharmacological approaches to effects of capsaicinoids and of classical antisecretory drugs on gastric basal acid secretion and on indomethacin-induced gastric mucosal damage in human healthy subjects (mini review).

BACKGROUND: Actions of various drugs have been tested on the gastric acid basal secretion and on the drug (Indomethacin)- induced gastric mucosal damage; however their physiological and pharmacological mechanisms have not been compared. AIMS: The effects of capsaicinoids, atropine, cimetidine, omeprazole, famotidine and ranitidine were studied on gastric basal acid output, whereas the gastric mucosal preventive effects of capsaicinoids (capsaicin), atropine and cimetidine were tested on the indomethacin-induced gastric mucosal microbleedings in human healthy subjects. Results were presented by molecular pharmacological method; affinity (pD) and intrinsic activity (α-values) were calculated. Intrinsic activity curves are based on comparison to atropine effect (α(atropine)= 1.00). For evaluation of physiological and pharmacological effects of compounds molar doses of pD(2) (necessary doses to produce 50% inhibition) and pA(2) (50% inhibion on intrinsic activity) were calculated from affinity and intrinsic activity curves. RESULTS: The pD(2) values for compounds were as follows: 5.88 for capsaicinoids, 5.40 for atropine , 2.23 for cimetidine, 3.33 for ranitidine, 3.77 for famotidine and 3.97 for omeprazole. α - value results for compounds were: 0.76 for capsaicinoids, and 1.00 for atropine, cimetidine, ranitidine, famotidine and omeprazole all equal to 1.00 on gastric acid basal secretion. The pD(2) values on indomethacin-induced gastric mucosal microbleeding were found as follows: 6.00 for capsaicinoids, 5.50 for atropine, and 3.50 for cimetidine, meanwhile α-values resulted 0.76 for capsaicinoids, 1.00 for atropine and cimetidine. CONCLUSIONS: Comparison classical antisecretory drugs acting on different pathways but in much more higher molar concentrations. The atropine and capsaicinoids act in about the same molar concentration which suggests a significant physiological role for capsaicin sensitive afferent nerves in the regulation of gastric basal acid secretion and in the prevention of chemically- induced gastric mucosal protection in human healthy subjects, suggesting a novel physiological pathway in regulation. These results clearly indicate the molecular pharmacological backgrounds of actions of classical antisecretory drugs and physiological role of capsaicin- sensitive afferent nerves in human healty subjects on the gastric basal secretion and on the prevention of drug-induced gastric mucosal damage.

Capsaicin-sensitive afferentation represents an indifferent defensive pathway from eradication in patients with H. pylori gastritis.

AIM: To study the role of capsaicin-sensitive afferent nerves in Helicobacter pylori (H. pylori) positive chronic gastritis before and after eradication. METHODS: Gastric biopsy samples were obtained from corpus and antrum mucosa of 20 healthy human subjects and 18 patients with H. pylori positive chronic gastritis (n = 18) before and after eradication. Traditional gastric mucosal histology (and Warthin-Starry silver impregnation) and special histochemical examinations were carried out. Immunohistochemistry for capsaicin receptor (TRVP1), calcitonin gene-related peptide (CGRP) and substance P (SP) were carried out by the labeled polymer immunohistological method (Lab Vision Co., USA) using polyclonal rabbit and rat monoclonal antibodies (Abcam Ltd., UK). RESULTS: Eradication treatment was successful in 16 patients (89%). Seven patients (7/18, 39%) remained with moderate complaints, meanwhile 11 patients (11/28, 61%) had no complaints. At histological evaluation, normal gastric mucosa was detected in 4 patients after eradication treatment (4/18, 22%), and moderate chronic gastritis could be seen in 14 (14/18, 78%) patients. Positive immuno-staining for capsaicin receptor was seen in 35% (7/20) of controls, 89% (16/18, P < 0.001) in patients before and 72% (13/18, P < 0.03) after eradication. CGRP was positive in 40% (8/20) of controls, and in 100% (18/18, P < 0.001) of patients before and in 100% (18/18, P < 0.001) after eradication. The immune-staining of gastric mucosa for substance-P was positive in 25% (5/20) of healthy controls, and in 5.5% (3/18, P > 0.05) of patients before and in 0% of patients (0/18, P > 0.05) after H. pylori eradication. CONCLUSION: Distibution of TRVP1 and CGRP is altered during the development of H. pylori positive chronic gastritis. The immune-staining for TRVP1, CGRP and SP rwemained unchanged before and after H. pylori eradication treatment. The capsaicin-sensitive afferentation is an independent from the eradication treatment. The 6 wk time period might not be enough time for the restituion of chronic H. pylori positive chronic gastritis. The H. pylori infection might not represent the main pathological factor in the development of chronic gastritis.

Approaches to gastrointestinal cytoprotection: from isolated cells, via animal experiments to healthy human subjects and patients with different gastrointestinal disorders.

Our clinical observations proved that the the duodenal ulcer in patients healed without any inhibition of gastric acid secretion (1965), and the healing rates of atropine vs cimetidine vs Carbenoxolone were equal and superior to that of placebo in randomized, prospective and multiclinical study of DU patients (1978). The phenomenon of gastric cytoprotection was defined by André Robert in rats (1979). The essential point of this phenomenon is that the prostaglandins prevent the chemical-induced gastric mucosal damage without affecting gastric acid secretion, this being originally suggested as a reaction specific to prostaglandins. Since then gastrointestinal cytoprotection has been shown with various agents (anticholinergic agents, H(2)RA, growth factors, body protecting compound, BPC) and retinoids in animals; the latter differing from the actions of vitamin A. In examining the various components of gastrointestinal cytoprotection , different studies have performed in isolated cells, stable cell lines, animal experiments, healthy human subjects, in patients chronic gastric and duodenal ulcers, and with different gastrointestinal disorders. Our attention has focused on the effects of cytoprotective agents on cellular viability, mitochondrial and DNA damage, oxygen free radicals, natural antioxidant systems, mucosal biochemistry, vascular events, gastrointestinal mucosal protection as well as in their prevention of different human diseases. This paper gives an overview on the different approaches for the exploring gastrointestinal cytoprotection (at the level of isolated cells, animal experiments, healthy human beings and patients with different gastrointestinal disorders). It has been indicated that the gastric cytoprotection exists in animals, human healthy subjects, patients with different gastrointestinal disorders. The our human observation in patients with duodenal ulcer healed without any changes of gastric acid secretion, there were no significant differences between the cimetidine vs. atropine (as antisecterory agents) or vs. Carbenoxolone vs. retinoid (as cytoprotective compounds) treatment. Also we indicated the presence of intact vagal nerve basically necessary for development of gastrointestinal cytoprotection and for capsaicin-sensitive vagal nerve induced mucosal protection (1982).

Serum prohepcidin levels in chronic inflammatory bowel diseases.

BACKGROUND AND AIMS: One of the major symptoms of chronic inflammatory bowel diseases is anemia. The two most common diseases are Crohn's disease and ulcerative colitis. Anemia may develop due to intestinal bleeding, iron absorption disturbances, or high levels of inflammatory cytokines. It is not clear whether or not hepcidin, the only known hormone regulating cellular iron uptake in mammals is involved. The transcription of hepcidin is controlled by the iron status of the body, hypoxia, and/or inflammation. This study was meant to find relationship between serum prohepcidin levels and clinical parameters of iron homeostasis or inflammatory state in patients suffering from Crohn's disease or ulcerative colitis. METHODS: Serum prohepcidin levels were measured with ELISA in 72 patients diagnosed with ulcerative colitis and 30 patients suffering from Crohn's disease. RESULTS: In both groups serum iron levels were lower, while levels of C-reactive protein were higher than in the healthy controls. Serum prohepcidin levels showed no significant differences compared to those in the control group. In the affected patients only weak correlations were observed between prohepcidin levels and diagnostic parameters: in Crohn's disease prohepcidin levels correlated positively with transferrin levels, total iron-binding capacity, transferrin saturation, activity index, and serum albumin levels, while in ulcerative coltitis prohepcidin levels were related to transferrin levels and transferrin saturation. CONCLUSION: It seems obvious that serum prohepcidin level determination in itself is not a satisfactory diagnostic or prognostic measure in anemia of chronic inflammatory bowel diseases.

Gastric cytoprotection 30 years after its discovery by André Robert: a personal perspective.

It is generally accepted that the development of gastric mucosal injury and protection is a consequence of an imbalance between the existing aggressive and defensive factors in the gastric mucosa. The excess secretion of gastric acid and increased production of pepsin have been considered as the main etiological factors in the development of peptic ulcer diseases in humans. André Robert and his coworkers (Kalamazoo, Michigan, USA) identified a new pathway for the gastric mucosal protection against the gastric mucosal damage injury (e.g. from HCl, NaOH, NaCl, ethanol, or thermal injury) by small doses of prostaglandins (1-5 µg/kg given ig or sc), without presence of any gastric acid secretory properties in rats. This phenomenon was termed "gastric cytoprotection" (1979). The results of this basic research offered a lot of new possibilities to test this hypothesis in different experimental models under different experimental conditions, in both human healthy subjects as well as in patients with various gastrointestinal disorders (acute and chronic gastrointestinal inflammatory conditions in the stomach and intestines, as well as GI precancerous states, i.e., oesophageal, stomach, pancreatic, liver and colon cancers). An international symposium on "gastric cytoprotection: 30 years after André Robert's concept" was organized at Split (Croatia) on September 13, 2009, at which invited experts from China, Croatia, Italy, Japan, Poland, and USA gave presentations and discussed the studies performed in the field of cytoprotection between 1979 and 2009. This paper provides a short critical summary of this meeting in the context of an "official historic background" of the events underlying the discovery of "gastric cytoprotection" which originated from the pioneering work of André Robert.

Production of orally applicable new drug or drug combinations from natural origin capsaicinoids for human medical therapy.

It is well known that the capsaicin stimulates (in small doses) or impairs (in high doses) the capsaicin-sensitive afferent nerves and the final effects of capsaicin depend on its applied doses. The effects of capsaicin were analyzed on the gastrointestinal mucosal protection and injury in animal experiments and in human beings (from 1980 up to now). From 2005 to 2008 an interdisciplinary group (21 researchers) participated in the production of orally applicable drug or drug combinations from capsaicin for human medical therapy of patients suffering from cardiovascular, degenerative joint and locomotor diseases, who received in their treatments non-steroidal anti-inflammatory compounds (NSAIDs). Our studies were based on the results of the NSAIDs-induced gastrointestinal side effects could be detected by application of small doses of capsaicin. Because natural (plant origin) capsaicin is chemically does not represent a uniform entity and used in the international research, consequently the authors met a lot of unpredictable scientific problems during the time of production of new capsaicin containing (alone or in combinations) drug before receiving official permissions from the different national and international authorities to start the classical human clinical pharmacological studies. This paper summarizes the different steps from the basic physiological and pharmacological notes (in animals), plant cultivation, chemistry of substance(s), animal (general and germinative) acute and chronic toxicology, human actions, basic clinical pharmacology of natural capsaicin (capsaicinoids) to introduce and to develop a new drug (or drug combinations) in the human medical therapy.

Interdisciplinary review for correlation between the plant origin capsaicinoids, non-steroidal antiinflammatory drugs, gastrointestinal mucosal damage and prevention in animals and human beings.

BACKGROUND: The plant origin capsaicinoids (capsaicin, dihydrocapsaicin, norcapsaicin, dihydrocapsaicin, homocapsaicin, homodihydrocapsaicin) are well known and used as nutritional additive agents in the every day nutritional practice from the last 9,500 years; however, we had have a very little scientifically based knowledge on their chemistry, physiology and pharmacology in animal observations, and in humans up to the mid-twentieth century. Our knowledge about their chemistry, physiology, pharmacology entered to be scientifically based evidence from the year 1980, dominantly in animal observations. The human observations with capsaicin (capsaicinoids), in terms of good clinical practice, have been started only in the last 10-year period (from 1997) in randomized, prospective, multiclinical studies. The name of "capsaicin" used only in the physiological and pharmacological research both in animal experiments and in human observation. The "capsaicin" (as a "chemically" used natural compound) modifies the so-called capsaicin-sensitive afferent nerves depending on their applied doses. AIMS: The specific action of capsaicin (capsaicinoids) on sensory afferent nerves modifying gastrointestinal (GI) function (under very specific conditions) offers a possibility for the production of an orally applicable drug or for other drug combinations, which can be used in the human medical therapy. The production of new drug is based on the critical interdisciplinary review of the results obtained with capsaicinoids. MATERIALS AND METHODS: This paper gives an interdisciplinary and critical overview on the chemical, physiological, pharmacological and toxicological actions of the natural origin capsaicinoids (from the point of drug production) under conditions of acute, subacute and chronic administration in animal experiments and human observations, toxicology, pharmacokinetics). This interdisciplinary review covers the following main chapters: (1) physiological and pharmacological research tool by capsaicin in the animals and human beings, (2) capsaicin research in animals (including the acute, subacute toxicology and chronic toxicology metabolism, genotoxicology), (3) capsaicin observation with capsaicin in human beings. CONCLUSION: (1) The capsaicin used in the physiological and pharmacological observations (in animals and human beings) chemically represents different chemical compounds, which can be obtained from the plants (paprika, chilli, etc.), (2) capsaicinoids are able to modify the capsaicin-sensitive afferent nerves, which have principle roles in the defence of different organs (including the gastrointestinal tract [against the different chemicals, heat, strech, chemical millieu-induced damage], (3) the application of capsaicin (capsaicinoids) can be repeated for the beneficial effects on the gastrointestinal tract as those in animal experiments. After this interdisciplinary and critical review, this paper demonstrates the well-planned research pathways of the discoveries of capsaicinoids from plant chemistry, via physiology, pharmacology and toxicology in animal experiments and human observations.

No association of the cytotoxic T-lymphocyte associated gene CTLA4 +49A/G polymorphisms with Crohn's disease and ulcerative colitis in Hungarian population samples.

AIM: The goal of the current work was to analyse the prevalence of the +49A/G variant of the cytotoxic T-lymphocyte antigen 4 gene (CTLA4) in Hungarian patients with Crohnos disease (CD) and ulcerative colitis (UC). METHODS: A total of 130 unrelated subjects with CD and 150 with UC, and 170 matched controls were genotyped for the single nucleotide polymorphism (SNP). The genotypes were determined by using PCR/RFLP test. RESULTS: The G allele frequency and the prevalence of the GG genotype were 38.1% and 12.3% in the CD group, 40.6% and 18.6% in the UC patients, and 37.4% and 15.9% in the control group, respectively. CONCLUSION: The results of the current study show that carriage of the +49G SNP in heterozygous or in homozygous form does not confer risk either for CD or for UC in the Hungarian population.

Plasma carnitine ester profiles in Crohn's disease patients characterized for SLC22A4 C1672T and SLC22A5 G-207C genotypes.

Crohn's disease (CD) is a chronic inflammatory bowel disorder caused by environmental and genetic factors. The purpose of this study was to analyse the possible influence of functional variants of genes of OCTN cation transporters on the carnitine ester profile of patients with CD. Genotyping for SLC22A4 1672C --> T, SLC22A5-207G --> C mutations and three common NOD2 variants (R702W, G908R and 1007finsC) were performed in 100 adult CD patients and in ninety-four healthy controls by direct sequencing. The carnitine ester profile was determined using ESI triple quadrupole tandem MS. Contrary to the NOD2/CARD15 mutations, none of the SLC variants showed increased prevalence in the CD group, the prevalence of TC haplotype did not differ between the patients and the controls. In the mixed group of CD patients the fasting propionyl- (0.243 (sem 0.008) v. 0.283 (sem 0.014) micromol/l), butyryl- (0.274 (sem 0.009) v. 0.301 (sem 0.013)) and isovalerylcarnitine (0.147 (sem 0.006) v. 0.185 (sem 0.009)) levels were decreased; while the level of octenoyl- (0.086 (sem 0.006) v. 0.069 (sem 0.005)), myristoleyl- (0.048 (sem 0.003) v. 0.037 (sem 0.003)), palmitoyl- (0.140 (sem 0.005) v. 0.122 (sem 0.004)) and oleylcarnitine (0.172 (sem 0.006) v. 0.156 (sem 0.008); P < 0.05 in all comparisons) were increased. After sorting the patients into SLC22A genotype-specific subgroups, no significant differences could be observed between them. The carnitine ester profile data suggest selective involvement of the carnitine esters in CD patients, probably due to their altered metabolism.

Molecular pharmacological approach to drug actions on the afferent and efferent fibres of the vagal nerve involved in gastric mucosal protection in rats.

BACKGROUND: Gastric mucosal protection is associated with the actions of anti-ulcer drugs or agents affecting on the afferent and/or efferent nerve fibres of the vagal nerve. AIMS: 1. To identify the dose-response curves of drugs (compounds) on the afferent vanilloid-receptor (capsaicin or resiniferatoxin-sensitive) and on efferent secretion (atropine, pirenzepine, cimetidine, ranitidine, famotidine, omeprazole, esomeprazole) basal gastric acid and stimulated gastric secretion in relation to the chemically-induced gastric mucosal damage in rats; 2. To determine the ED50 (pD2) and pA2 on the calculation of affinity and intrinsic affinity curves for these agonists/antagonists, as an indication of relative potency of effects. MATERIALS AND METHODS: The observations were carried out in rats (30 different models). RESULTS: The ED50 values for affinities of capsaicin, resiniferatoxin were obtained in nmol/kg b.w. range, whereas the values were in the nmol/kg to micromol/kg b.w. ranges for effects on the gastric basal, stimulated (bethanechol, pentagastrin, histamine) gastric secretion, and the gastric mucosal damage-produced by different ulcerogenic agents (ethanol, HCl, aspirin, indomethacin). CONCLUSION: From the observations, that agents acting on vanilloid (capsaicin) receptors were the most potent inhibitors of acid secretion and gastric lesions from necrotizing agents, suggests that the capsaicin sensitive afferent nerves have a primary place in the efferent regulated events leading to initiation of gastric mucosal damage.

Prevalence of SLC22A4, SLC22A5 and CARD15 gene mutations in Hungarian pediatric patients with Crohn's disease.

AIM: To investigate the frequency of the common NOD2/CARD15 susceptibility variants and two functional polymorphisms of OCTN cation transporter genes in Hungarian pediatric patients with Crohn's disease (CD). METHODS: A cohort of 19 unrelated pediatric and 55 unrelated adult patients with Crohn's disease and 49 healthy controls were studied. Genotyping of the three common CD-associated CARD15 variants (Arg702Trp, Gly908Arg and 1007finsC changes) with the SLC22A4 1672C-->T, and SLC22A5 -207G-->C mutations was performed by direct sequencing of the specific regions of these genes. RESULTS: At least one CARD15 mutation was present in 52.6% of the children and in 34.5% of the adults compared to 14.3% in controls. Surprisingly, strongly different mutation profile was detected in the pediatric versus adult patients. While the G908R and 1007finsC variants were 18.4% and 21.1% in the pediatric group, they were 1.82% and 11.8% in the adults, and were 1.02% and 3.06% in the controls, respectively. The R702W allele was increased approximately two-fold in the adult subjects, while in the pediatric group it was only approximately 64% of the controls (9.09% in the adults, 2.63% in pediatric patients, and 4.08% in the controls). No accumulation of the OCTN variants was observed in any patient group versus the controls. CONCLUSION: The frequency of the NOD2/CARD15 susceptibility variants in the Hungarian pediatric CD population is high and the profile differs from the adult CD patients, whereas the results for SLC22A4 and SLC22A5 mutation screening do not confirm the assumption that the carriage of these genotypes means an obligatory susceptibility to CD.