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1.
Eur J Neurosci ; 51(6): 1403-1418, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31465599

RESUMO

The olfactory mucosa (OM) is the primary site of odorant detection, and its axonal projections relay information to brain structures for signal processing. We have previously observed that olfactory function can be affected during a prolonged stress challenge in Wistar rats. The stress response is a neuroendocrine retro-controlled loop allowing pleiotropic adaptive tissue alterations, which are partly mediated through the release of glucocorticoid hormones. We hypothesised that, as part of their wide-ranging pleiotropic effects, glucocorticoids might affect the first step of olfactory detection. To study this, we used a number of approaches ranging from the molecular detection and functional characterisation of glucocorticoid receptors (GRs) in OM cells, to the study of GR acute activation in vivo at the molecular, electrophysiological and behavioural levels. In contrast to previous reports, where GR was reported to be exclusive in olfactory sensory neurones, we located functional GR expression mostly in olfactory ensheathing cells. Dexamethasone (2 mg/kg) was injected intraperitoneally to activate GR in vivo, and this led to functional odorant electrophysiological response (electro-olfactogram) and OM gene expression changes. In a habituation/cross-habituation test of olfactory sensitivity, we observed that DEX-treated rats exhibited higher responsiveness to a complex odorant mixture. These findings support the idea that olfactory perception is altered in stressed animals, as glucocorticoids might enhance odour detection, starting at the first step of detection.


Assuntos
Glucocorticoides , Mucosa Olfatória , Animais , Glucocorticoides/farmacologia , Ratos , Ratos Wistar , Receptores de Glucocorticoides , Olfato
2.
Eur J Neurosci ; 45(12): 1613-1622, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28452078

RESUMO

Most of biological variables follow a daily rhythm. It holds true as well for sensory capacities as two decades of research have demonstrated that the odorant induced activity in the olfactory bulbs oscillates during the day. Olfactory bulbs are the first central nervous system structures, which receive inputs from the olfactory neurons located in the nose olfactory epithelium in vertebrates. So far, data on variation in odorant detection in the olfactory epithelium throughout the day are missing. Using electroolfactogram recordings in rats housed under daily light and dark cycles, we found that the olfactory epithelium responsiveness varies during the day with a maximum in the beginning of the light phase. This fluctuation was consistent with cycling of transduction pathway gene expression in the olfactory epithelium examined by qPCR. It was also consistent with the levels of two transduction pathway proteins (olfactory-type G protein and adenylyl cyclase III) examined by western blot. Daily variations were also observed at the level of olfactory sensory neurons responses recorded by patch-clamp. To rule out a potential effect of the feeding status of the animal, we examined the variation in odorant response in starved animals during the day. We observed a similar pattern to ad libidum fed animals. Taken together, our results reveal that the olfactory epithelium sensitivity varies during the day in part due to modulation of the very first step of odorant detection.


Assuntos
Ritmo Circadiano , Mucosa Olfatória/fisiologia , Percepção Olfatória , Adenilil Ciclases/genética , Adenilil Ciclases/metabolismo , Animais , Canais de Cátion Regulados por Nucleotídeos Cíclicos/genética , Canais de Cátion Regulados por Nucleotídeos Cíclicos/metabolismo , Subunidades alfa de Proteínas de Ligação ao GTP/genética , Subunidades alfa de Proteínas de Ligação ao GTP/metabolismo , Masculino , Bulbo Olfatório/fisiologia , Mucosa Olfatória/metabolismo , Proteínas Proto-Oncogênicas c-fos/genética , Proteínas Proto-Oncogênicas c-fos/metabolismo , Ratos , Ratos Wistar , Receptores Odorantes/genética , Receptores Odorantes/metabolismo
3.
Stem Cells ; 29(5): 812-24, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21433223

RESUMO

Because stem cells are often found to improve repair tissue including heart without evidence of engraftment or differentiation, mechanisms underlying wound healing are still elusive. Several studies have reported that stem cells can fuse with cardiomyocytes either by permanent or partial cell fusion processes. However, the respective physiological impact of these two processes remains unknown in part because of the lack of knowledge of the resulting hybrid cells. To further characterize cell fusion, we cocultured mouse fully differentiated cardiomyocytes with human multipotent adipose-derived stem (hMADS) cells as a model of adult stem cells. We found that heterologous cell fusion promoted cardiomyocyte reprogramming back to a progenitor-like state. The resulting hybrid cells expressed early cardiac commitment and proliferation markers such as GATA-4, myocyte enhancer factor 2C, Nkx2.5, and Ki67 and exhibited a mouse genotype. Interestingly, human bone marrow-derived stem cells shared similar reprogramming properties than hMADS cells but not human fibroblasts, which suggests that these features might be common to multipotent cells. Furthermore, cardiac hybrid cells were preferentially generated by partial rather than permanent cell fusion and that intercellular structures composed of f-actin and microtubule filaments were involved in the process. Finally, we showed that stem cell mitochondria were transferred into cardiomyocytes, persisted in hybrids and were required for somatic cell reprogramming. In conclusion, by providing new insights into previously reported cell fusion processes, our data might contribute to a better understanding of stem cell-mediated regenerative mechanisms and thus, the development of more efficient stem cell-based heart therapies.


Assuntos
Fusão Celular , Células-Tronco Mesenquimais/citologia , Mitocôndrias/metabolismo , Miócitos Cardíacos/citologia , Animais , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Linhagem Celular , Células Cultivadas , Reprogramação Celular/genética , Reprogramação Celular/fisiologia , Fibroblastos/citologia , Fibroblastos/metabolismo , Humanos , Imuno-Histoquímica , Hibridização In Situ , Masculino , Células-Tronco Mesenquimais/metabolismo , Camundongos , Miócitos Cardíacos/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
4.
J Sex Med ; 9(11): 2827-37, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22908904

RESUMO

INTRODUCTION: Animal models of urinary incontinence and erectile dysfunction following radical prostatectomy (RP) are lacking. AIMS: To develop an animal model of combined post-RP urethral sphincter and erectile dysfunctions, and noninvasive methods to assess erectile function (EF) and urinary sphincter function (USF) during prolonged follow-up. METHODS: In the main experiments, 60 male Sprague Dawley rats were randomized to a sham operation (N = 30) or electrocautery of both sides of the striated urethral sphincter (N = 30). EF and USF were evaluated preoperatively and on postoperative days 7, 15, 30, 60, and 90. Sphincter and penile tissue samples were evaluated histologically on days 7 (N = 10) and 30 (N = 10) to detect apoptosis (TUNEL assays) and fibrosis (Trichrome Masson staining). MAIN OUTCOME MEASURES: To assess EF, we measured systemic and penile blood flow using penile laser Doppler and penile rigidity using a durometer before and after apomorphine injection. USF was assessed based on the retrograde leak point pressure (LPPr). RESULTS: Apomorphine increased baseline Doppler flow by 180% (95% confidence interval, 156-202%) and penile hardness from 3.49 ± 0.5 to 7.16 ± 0.82 Shore A units but did not change systemic arterial flow. Mean LPPr was 76.8 ± 6.18 mm Hg at baseline and decreased by 50% after injury, with no response to apomorphine on day 7. EF and USF impairments persisted up to 90 days post injury. Histology showed penile apoptosis on day 7 and extensive urethral sphincter and penile fibrosis on day 30. Our data did not allow us to determine whether the impairment in erectile response to apomorphine preponderantly reflected arterial penile insufficiency or veno-occlusive dysfunction. CONCLUSION: Electrocautery of the striated urethral sphincter caused severe and lasting impairment of EF and USF that could be monitored repeatedly using minimally invasive methods. This new animal model may hold potential for developing new treatments designed to correct post-RP impairments.


Assuntos
Modelos Animais de Doenças , Impotência Vasculogênica/fisiopatologia , Complicações Pós-Operatórias/fisiopatologia , Prostatectomia , Uretra/fisiopatologia , Incontinência Urinária/fisiopatologia , Animais , Apoptose/fisiologia , Seguimentos , Masculino , Ereção Peniana/fisiologia , Ratos , Ratos Sprague-Dawley , Urodinâmica/fisiologia
5.
J Neurosci ; 30(18): 6323-33, 2010 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-20445058

RESUMO

The response of insect olfactory receptor neurons (ORNs) to odorants involves the opening of Ca(2+)-permeable channels, generating an increase in intracellular Ca(2+) concentration. Here, we studied the downstream effect of this Ca(2+) rise in cultured ORNs of the moth Spodoptera littoralis. Intracellular dialysis of Ca(2+) from the patch pipette in whole-cell patch-clamp configuration activated a conductance with a K(1/2) of 2.8 microm. Intracellular and extracellular anionic and cationic substitutions demonstrated that Cl(-) carries this current. The anion permeability sequence I(-) > NO(3)(-) > Br(-) > Cl(-) > CH(3)SO(3)(-) >> gluconate(-) of the Ca(2+)-activated Cl(-) channel suggests a weak electrical field pore of the channel. The Ca(2+)-activated current partly inactivated over time and did not depend on protein kinase C (PKC) and CaMKII activity or on calmodulin. Application of Cl(-) channel blockers, flufenamic acid, 5-nitro-2-(3-phenylpropylamino) benzoic acid, or niflumic acid reversibly blocked the Ca(2+)-activated current. In addition, lowering Cl(-) concentration in the sensillar lymph bathing the ORN outer dendrites caused a significant delay in pheromone response termination in vivo. The present work identifies a new Cl(-) conductance activated by Ca(2+) in insect ORNs presumably required for ORN repolarization.


Assuntos
Cálcio/fisiologia , Canais de Cloreto/fisiologia , Potenciais da Membrana/fisiologia , Neurônios Receptores Olfatórios/fisiologia , Spodoptera/fisiologia , Animais , Ânions/metabolismo , Cálcio/farmacologia , Sinalização do Cálcio/efeitos dos fármacos , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/antagonistas & inibidores , Calmodulina/farmacologia , Técnicas de Cultura de Células/métodos , Canais de Cloreto/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Masculino , Potenciais da Membrana/efeitos dos fármacos , Moduladores de Transporte de Membrana/farmacologia , Neurônios Receptores Olfatórios/efeitos dos fármacos , Permeabilidade , Feromônios/farmacologia , Proteína Quinase C/antagonistas & inibidores , Spodoptera/efeitos dos fármacos , Spodoptera/metabolismo
6.
Oncotarget ; 8(3): 4330-4341, 2017 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-28032594

RESUMO

Olfactory receptors are G protein-coupled receptors. Some of them are expressed in tumor cells, such as the OR51E2 receptor overexpressed in LNCaP prostate cancer cells. It is considered a prostate tumor marker. We previously demonstrated that this receptor is able to promote LNCaP cell invasiveness in vitro upon stimulation with its odorant agonist ß-ionone, leading to increased generation of metastases in vivo. In the present study, we show that even a relatively short exposure to ß-ionone is sufficient to promote metastasis emergence. Moreover, α-ionone, considered an OR51E2 antagonist, in fact promotes prostate tumor growth in vivo. The combination of α-ionone with ß-ionone triggers a higher increase in the total tumor burden than each molecule alone. To support the in vivo results, we demonstrate in vitro that α-ionone is a real agonist of OR51E2, mainly sustaining LNCaP cell growth, while ß-ionone mainly promotes cell invasiveness. So, while structurally close, α-ionone and ß-ionone appear to induce different cellular effects, both leading to increased tumor aggressiveness. This behaviour could be explained by a different coupling to downstream effectors, as it has been reported for the so-called biased ligands of other G protein-coupled receptors.


Assuntos
Proteínas de Neoplasias/agonistas , Norisoprenoides/farmacologia , Neoplasias da Próstata/patologia , Receptores Odorantes/agonistas , Animais , Linhagem Celular Tumoral , Movimento Celular , Progressão da Doença , Humanos , Masculino , Camundongos , Metástase Neoplásica , Transplante de Neoplasias , Norisoprenoides/química , Neoplasias da Próstata/metabolismo , Regulação para Cima
7.
BMC Res Notes ; 10(1): 541, 2017 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-29084601

RESUMO

OBJECTIVE: We previously reported that the olfactory receptor OR51E2, overexpressed in LNCaP prostate cancer cells, promotes cell invasiveness upon stimulation of its agonist ß-ionone, and this phenomenon increases metastatic spread. Furthermore, we showed that the induced cell invasiveness involves a PI3 kinase dependent signalling pathway. We report here the results of a new investigation to address whether gallein, a small inhibitor of G protein ßγ subunit interaction with PI3 kinase, can inhibit ß-ionone effects both in vitro and in vivo. RESULTS: We demonstrate that gallein can inhibit the ß-ionone-induced cell invasiveness in vitro, as well as the spread of metastases in vivo. LNCaP cell invasiveness, assessed using spheroid cultures in collagen gels in vitro, was increased by ß-ionone and the effect was reversed by co-administration of gallein. LNCaP tumour cells, subcutaneously inoculated to immunodeficient mice, generated more metastases in vivo when ß-ionone was applied through the skin. Furthermore, the intraperitoneal injection of gallein inhibited this increased metastasis spread. Our results thus support the role of OR51E2 in the ß-ionone observed effects, and suggest that gallein could be a potential new agent in personalized medicine of the tumours expressing OR51E2.


Assuntos
Subunidades beta da Proteína de Ligação ao GTP/metabolismo , Subunidades gama da Proteína de Ligação ao GTP/metabolismo , Proteínas de Neoplasias/metabolismo , Norisoprenoides/metabolismo , Neoplasias da Próstata/metabolismo , Receptores Odorantes/metabolismo , Xantenos/farmacologia , Animais , Linhagem Celular Tumoral , Humanos , Masculino , Camundongos , Invasividade Neoplásica , Metástase Neoplásica , Neoplasias da Próstata/tratamento farmacológico , Transdução de Sinais , Células Tumorais Cultivadas , Xantenos/administração & dosagem
8.
Behav Brain Res ; 291: 36-45, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26003942

RESUMO

For most animal species, olfaction plays a paramount role in their perception of the environment. Odours are initially detected in neurons located in the olfactory mucosa. This tissue is regulated by several physiological signals and can be altered in pathology. A number of clinical studies suggest an association between depressive disorders and olfactory sensory loss. In rodents, depressive-like states can be observed in models of chronic stress. We tested the hypothesis that olfactory function might be altered in a rat model of depression, induced by chronic variable stress (CVS). While CVS rats exhibited several symptoms consistent with chronic stress exposure and depressive-like states (increased sucrose intake in sucrose preference test, increased immobility in forced swim test, hyperlocomotion), their odorant responses recorded at the olfactory mucosa level by electro-olfactogram were decreased. In addition we observed increased apoptosis markers in the olfactory mucosa using Western Blot. Our data are consistent with reduced olfactory capacities in a laboratory rat model of chronic stress and depression, in agreement with human clinical data; this warrants further mechanistic studies. Furthermore, this works raises the possibility that altered olfactory function might be a confounding factor in the behavioural testing of chronically stressed or depressed rats.


Assuntos
Transtorno Depressivo/fisiopatologia , Mucosa Olfatória/fisiopatologia , Olfato/fisiologia , Estresse Psicológico/fisiopatologia , Animais , Apoptose/fisiologia , Doença Crônica , Transtorno Depressivo/patologia , Sacarose Alimentar , Modelos Animais de Doenças , Comportamento Alimentar/fisiologia , Masculino , Atividade Motora/fisiologia , Neurônios/fisiologia , Mucosa Olfatória/patologia , Ratos Wistar , Estresse Psicológico/patologia , Natação/fisiologia
9.
Chem Senses ; 32(4): 305-17, 2007 May.
Artigo em Inglês | MEDLINE | ID: mdl-17267420

RESUMO

The role of Ca(2+) in insect olfactory transduction was studied in the moth Spodoptera littoralis. Single sensillum recordings were made to investigate in vivo the role of sensillar Ca(2+) on the electrophysiological properties of sex pheromone responsive olfactory receptor neurons (ORNs). Lowering the sensillar Ca(2+) concentration to 2 x 10(-8) M increased ORN spontaneous firing activity and induced long bursts of action potentials (APs) superimposed on spontaneous negative deflections of the transepithelial potential. We inferred that Ca(2+) stabilizes the membrane potential of ORNs, keeping the spontaneous firing activity at a low and regular level. Neither the amplitude and kinetics of the rising phase of sensillar potentials (SPs) recorded in response to pheromone stimuli nor the AP generation during stimulation depended on the extracellular Ca(2+) concentration. Thus, extracellular Ca(2+) is not absolutely necessary for ORN response. Partial inhibition of responses with a calmodulin antagonist, W-7, also indicates that intracellular Ca(2+) contributes to the ORN response and suggests that Ca(2+) release from internal stores is involved. In 2 x 10(-8) M Ca(2+), the repolarization of the SP was delayed when compared with higher Ca(2+) concentrations. Therefore, in contrast to depolarization, ORN repolarization depends on extracellular Ca(2+). Ca(2+)-gated K(+) channels identified from cultured ORNs with whole-cell recordings are good candidates to mediate ORN repolarization.


Assuntos
Cálcio/fisiologia , Potenciais Evocados , Neurônios Receptores Olfatórios/fisiologia , Spodoptera/fisiologia , Animais , Células Cultivadas , Masculino , Neurônios Receptores Olfatórios/efeitos dos fármacos , Técnicas de Patch-Clamp , Feromônios/farmacologia
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