Browsing by Subject "TRPV1"

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  • Heiskanen, Vilma (Helsingin yliopisto, 2021)
    Binge eating disorder (BED) is the most common eating disorder characterized by compulsive recurrent binge eating episodes with the sense of a lack of control. During a binge eating episode, one eats a larger amount of food, typically high in fat and/or sugar, than would normally be eaten in a discrete period of time. After the episode, negative emotions, such as shame and self-disgust, are present. However, BED does not include compensatory behavior, such as vomiting or excessive exercise. Due to compulsive and uncontrollable eating behavior, it has been suggested that BED represents a food addiction. Eating energy-dense food activates the dopamine, opioid, and endocannabinoid systems in the brain. This elicits the activation of the reward process. Some drugs and medications affect the same neurotransmitter systems, which may produce neuronal alterations in the reward process, leading to an addiction. Several studies have found that cannabidiol (CBD) reduces the self- administration of cocaine, morphine, alcohol, and sucrose in rodents, suggesting an effect on the reward-response. Some of these effects have been shown to be mediated by cannabinoid receptor 2 and TRPV1 receptor. However, the effects of CBD on bingeing behavior have not been studied up to date. The aim of the study was to investigate the effect of CBD on homeostatic feeding and binge eating behavior in C57BL/6 mice. Five separate experiments were conducted. The first experiment investigated the effect of CBD (15, 50, and 150 mg/kg, i.p.) on locomotor activity in a modified open field test over a 2-hour period. In the second test, the effect of CBD (15, 50, and 150 mg/kg, i.p.) on homeostatic feeding was monitored in non-bingeing mice. Next, a limited intermittent access binge eating model without food deprivation or stressors was inducted. Mice had access to laboratory chow ad libitum, but a high energy diet (high in fat, HED) was presented in 24-hour periods every 5-8 days. Then the effect of CBD (15, 50, and 150 mg/kg, i.p.) on HED and chow intake in bingeing mice was investigated. In the fourth experiment, seven days following the administration, the after effect of CBD was studied by monitoring food intake without CBD treatment. Finally, it was investigated whether the effect of CBD can be inhibited by TRPV1 receptor antagonist AMG9810 (1 mg/kg, i.p). In each test, the food intake was monitored at the time point 0,5, 2,5, and 24 h after CBD treatment. Also, water consumption was measured in each experiment. The results revealed that CBD does not affect locomotor activity or homeostatic feeding at a dose of 15, 50, or 150 mg/kg (i.p). However, the results showed that CBD reduces the intake of HED in a dose-dependent manner (15, 50, or 150 mg/kg; i.p.) and, possibly, increases chow intake. No after effect was observed seven days following the administration. Most likely, TRPV1 does not mediate the effect of CBD on HED intake. Furthermore, no significant effects on water intake were observed. In this study, the core aims were to evaluate whether CBD affects homeostatic feeding or binge eating behavior in mice. The results provided a novel insight into the effects of CBD. The findings indicate that the acute systemic administration of CBD reduces HED intake, and possibly, simultaneously increases chow intake, suggesting a balancing effect on feeding in bingeing mice. However, the role of TRPV1 in this effect remains unclear, and further studies are needed.
  • Diniz, Cassiano R. A. F.; Biojone, Caroline; Joca, Samia R. L.; Rantamäki, Tomi; Castren, Eero; Guimaraes, Francisco S.; Casarotto, Plinio C. (2019)
    Background. Administration of anandamide (AEA) or 2-arachidonoylglycerol (2AG) induces CB1 coupling and activation of TRKB receptors, regulating the neuronal migration and maturation in the developing cortex. However, at higher concentrations AEA also engages vanilloid receptor TRPV1, usually with opposed consequences on behavior. Methods and Results. Using primary cell cultures from the cortex of rat embryos (E18) we determined the effects of AEA on phosphorylated TRKB (pTRK). We observed that AEA (at 100 and 200 nM) induced a significant increase in pTRK levels. Such effect of AEA at 100 nM was blocked by pretreatment with the CBI antagonist AM251 (200 nM) and, at the higher concentration of 200 nM by the TRPV1 antagonist capsazepine (200 nM), but mildly attenuated by AM251. Interestingly, the effect of AEA or capsaicin (a TRPV1 agonist, also at 200 nM) on pTRK was blocked by TRKB.Fc (a soluble form of TRKB able to bind BDNF) or capsazepine, suggesting a mechanism dependent on BDNF release. Using the marble-burying test (MBT) in mice, we observed that the local administration of ACEA (a CBI agonist) into the prelimbic region of prefrontal cortex (PL-PFC) was sufficient to reduce the burying behavior, while capsaicin or BDNF exerted the opposite effect, increasing the number of buried marbles. In addition, both ACEA and capsaicin effects were blocked by previous administration of k252a (an antagonist of TRK receptors) into PL-PFC. The effect of systemically injected CB1 agonist WIN55,212-2 was blocked by previous administration of k252a. We also observed a partial colocalization of CBI /TRPV1 /TRKB in the PL-PFC, and the localization of TRPV1 in CaMK2+ cells. Conclusion. Taken together, our data indicate that anandamide engages a coordinated activation of TRKB, via CB1 and TRPV1. Thus, acting upon CBI. and TRPV1, AEA could regulate the TRKB-dependent plasticity in both pre- and postsynaptic compartments.
  • Bousquet, Jean; Le Moing, Vincent; Blain, Hubert; Czarlewski, Wienczyslawa; Zuberbier, Torsten; Torre, Raphael de la; Lozano, Nieves Pizarro; Reynes, Jacques; Bedbrook, Anna; Cristol, Jean-Paul; Cruz, Alvaro A.; Fiocchi, Alessandro; Haahtela, Tari; Iaccarino, Guido; Klimek, Ludger; Kuna, Piotr; Melén, Erik; Mullol, Joaquim; Samolinski, Boleslaw; Valiulis, Arunas; Anto, Josep M. (2021)
    COVID-19 is described in a clinical case involving a patient who proposed the hypothesis that Nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-interacting nutrients may help to prevent severe COVID-19 symptoms. Capsules of broccoli seeds containing glucoraphanin were being taken before the onset of SARS-CoV-2 infection and were continued daily for over a month after the first COVID-19 symptoms. They were found to reduce many of the symptoms rapidly and for a duration of 6-12 h by repeated dosing. When the patient was stable but still suffering from cough and nasal obstruction when not taking the broccoli capsules, a double-blind induced cough challenge confirmed the speed of onset of the capsules (less than 10 min). A second clinical case with lower broccoli doses carried out during the cytokine storm confirmed the clinical benefits already observed. A third clinical case showed similar effects at the onset of symptoms. In the first clinical trial, we used a dose of under 600 mmol per day of glucoraphanin. However, such a high dose may induce pharmacologic effects that require careful examination before the performance of any study. It is likely that the fast onset of action is mediated through the TRPA1 channel. These experimental clinical cases represent a proof-of-concept confirming the hypothesis that Nrf2interacting nutrients are effective in COVID-19. However, this cannot be used in practice before the availability of further safety data, and confirmation is necessary through proper trials on efficacy and safety.
  • Leimuranta, Pinja; Khiroug, Leonard; Giniatullin, Rashid (2018)
    In this mini-review, we summarize recent discoveries and present new hypotheses on the role of cannabinoids in controlling trigeminal nociceptive system underlying migraine pain. Individual sections of this review cover key aspects of this topic, such as: (i) the current knowledge on the endocannabinoid system (ECS) with emphasis on expression of its components in migraine related structures; (ii) distinguishing peripheral from central site of action of cannabinoids, (iii) proposed mechanisms of migraine pain and control of nociceptive traffic by cannabinoids at the level of meninges and in brainstem, (iv) therapeutic targeting in migraine of monoacylglycerol lipase and fatty acid amide hydrolase, enzymes which control the level of endocannabinoids; (v) dual (possibly opposing) actions of cannabinoids via anti-nociceptive CB1 and CB2 and pro-nociceptive TRPV1 receptors. We explore the cannabinoid-mediated mechanisms in the frame of the Clinical Endocannabinoid Deficiency (CECD) hypothesis, which implies reduced tone of endocannabinoids in migraine patients. We further discuss the control of cortical excitability by cannabinoids via inhibition of cortical spreading depression (CSD) underlying the migraine aura. Finally, we present our view on perspectives of Cannabis-derived (extracted or synthetized marijuana components) or novel endocannabinoid therapeutics in migraine treatment.
  • Uunila, Oona (Helsingfors universitet, 2017)
    Hevosen kesäihottuma (engl. insect bite hypersensitivity, IBH) on tyypin I yliherkkyysreaktio Culicoides spp. -lajin hyönteisille. Yliherkkyysreaktiota tavataan kaikilla mantereilla kaikilla alueilla, joissa hyönteislajia esiintyy, lukuun ottamatta pieniä maantieteellisesti eristettyjä alueita. Suomessa lajista esiintyy Culicoiden nubeculos:ta ja C. obsoletus:ta. Yliherkkyyden esiintyvyys vaihtelee 3 %:sta 60 %:iin ja se koetaan omistajien keskuudessa haastavaksi ja vaikeaksi taudiksi. Hevosen kesäihottumassa hevosen immuunivasteen T-auttajasolupopulaatio (Th) kääntyy normaalin terveen hevosen Th1- soluvasteesta Th2-soluvasteen puolelle aiheuttaen allergeenille spesifisen vasta-aineen immunoglobuliini E:n (IgE) ylituotannon immunoglobuliini G:n ja A:n sijasta. Immunologisen vasteen muutokseen vaikuttaa major histocombatibility II (MHCII)- allergeeniesittelijämolekyylin geenin monimuotoisuus sekä vallitseva sytokiiniprofiili. Akuuteissa ja kroonisissa taudeissa on havaittu Th-soluvasteen ja sytokiinien eroavaisuuksia ja siten hankaloittaa taudin kulun ja hoitovaihtoehtojen tutkimista. Kesäihottuman diagnosointi perustuu esitietoihin, kliiniseen tutkimukseen ja taudin kausiluontoisuuteen. Allergeenipaneeleja on kehitetty luomaan uusi diagnosointimenetelmä. Myös ihmisillä ja koirilla on tyypin I yliherkkyyttä, atooppista dermatiittiä eli atopiaa. Ihmisen ja koiran yliherkkyyksistä on runsaammin tutkimuksia kuin hevosten ja taudeissa on huomattavia yhtäläisyyksiä, joita voidaan käyttää apuna kesäihottuman tutkimuksessa. Koiran ja ihmisten atopia noudattavat sytokiiniprofiililtaan hevosen kesäihottumaa kroonisissa ja akuuteissa taudinkuvissa. Kutinan syntymekanismia on tutkittu hiiri- ja koiramallein ja kutinasytokiineja ovat mm. histamiini ja interleukiini 31 (IL-31). Histamiinia vapautuu syöttösolujen pinnalle kiinnittyneen allergeenispesifisen IgE:n kohdatessa allergeenin. IL-31 on Th2-solujen tuottama soluvälittäjäaine, joka aiheuttaa kutinaa. Hevosilla IL-31 -välitteistä kutinaa ei ole raportoitu. Myös serotoniini, asetyylikoliini, substanssi P, eri leukotrieenit ja bradykiniinit, proteaasit ja lysofostidiinihappo aiheuttavat kutinaa eri signaalireittien kautta. Yhtenä yhdistävänä, epäspesifisenä signaalireittinä pidetään Transient Receptor Potential Vallinoid 1:stä (TRPV1), joka aktivoituu toissijaisesti hermosolun depolarisoituessa muiden kutinaa aiheuttavien sytokiinien läsnäollessa. Vastaavia tutkimuksia hevosilla ei ole tehty. Kesäihottuman lääkkeelliset hoitovaihtoehdot ovat kutinan hillitseminen kortisonilla, mutta ei sovellu pirkäaikaiskäyttöön. Teoriassa on mahdollista käyttää koiran atopiassa käytettävää oklasitinibiä kutinan hillitsemiseksi myös kesäihottumassa, mikäli hevosen kutinamekanismi on yhteneväinen koiran kutinan signaalireittien kanssa. Siklosporiinia käytetään koirien ja ihmisten atopiaan, mutta se toimii parhaiten Th1-soluvasteen torjumiseen. Antihistamiinien teho hevosella on huono. Nykyinen markkinoilla oleva siedätyshoito koetaan kalliiksi ja hoitovasteeltaan huonoksi. Uudet tutkimukset apuaineen kanssa injektoidusta allergeenistä ovat lupaavia, mutta vaativat lisätutkimuksia. Muut hoitovaihtoehdot ovat tieteellisiltä perusteiltaan heikkoja, näyttö puuttuu täysin tai tutkimukset ovat olleet heikkolaatuisia. Hevosen kesäihottuman diagnostiikka on toistaiseksi haastavaa ja hoitovaihtoehdot heikohkot tieteelliseltä näytöltään.