RESUMO
A single sub-anesthetic dose of ketamine exerts rapid and sustained antidepressant effects. Here, we examined the role of the ventral hippocampus (vHipp)-medial prefrontal cortex (mPFC) pathway in ketamine's antidepressant response. Inactivation of the vHipp with lidocaine prevented the sustained, but not acute, antidepressant-like effect of ketamine as measured by the forced swim test (FST). Moreover, optogenetic as well as pharmacogenetic specific activation of the vHipp-mPFC pathway using DREADDs (designer receptors exclusively activated by designer drugs) mimicked the antidepressant-like response to ketamine; importantly, this was pathway specific, in that activation of a vHipp to nucleus accumbens circuit did not do this. Furthermore, optogenetic inactivation of the vHipp/mPFC pathway at the time of FST completely reversed ketamine's antidepressant response. In addition, we found that a transient increase in TrkB receptor phosphorylation in the vHipp contributes to ketamine's sustained antidepressant response. These data demonstrate that activity in the vHipp-mPFC pathway is both necessary and sufficient for the antidepressant-like effect of ketamine.
Assuntos
Ketamina/metabolismo , Ketamina/farmacologia , Animais , Antidepressivos/farmacologia , Comportamento Animal/efeitos dos fármacos , Depressão/tratamento farmacológico , Hipocampo/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Optogenética/métodos , Córtex Pré-Frontal/metabolismo , NataçãoRESUMO
We experimentally study the temporal dynamics of amplitude-modulated laser beams propagating through a water dispersion of graphene oxide sheets in a fiber-to-fiber U-bench. Nonlinear refraction induced in the sample by thermal effects leads to both phase reversing of the transmitted signals and dynamic hysteresis in the input-output power curves. A theoretical model including beam propagation and thermal lensing dynamics reproduces the experimental findings.
RESUMO
Functional properties of protein from mantle and fin of the jumbo squid Dosidicus gigas were explained based on microscopic muscle fiber and protein fractions profiles as observed in SDS-PAGE. Fin has higher content of connective tissue and complex fiber arrangement, and we observed higher hardness of fin gels as expected. Myosin heavy chain (MHC) was found in sarcoplasmic, myofibril and soluble-in-alkali fractions of mantle and only in sarcoplasmic and soluble-in-alkali fractions of fin. An additive effect of salt concentration and pH affected the solubility and foaming properties. Fin and mantle proteins yielded similar results in solubility tests, but significant differences occurred for specific pH and concentrations of salt. Foaming capacity was proportional to solubility; foam stability was also affected by pH and salt concentration. Hardness and fracture strength of fin gels were significantly higher than mantle gels; gels from proteins of both tissues reached the highest level in the folding test. Structural and molecular properties, such as MHC and paramyosin solubility, arrangement of muscle fibers and the content of connective tissue were useful to explain the differences observed in these protein properties. High-strength gels can be formed from squid mantle or fin muscle. Fin displayed similar or better properties than mantle in all tests.
Assuntos
Decapodiformes , Congelamento , Proteínas Musculares/química , Animais , Análise de Alimentos , Concentração de Íons de Hidrogênio , Concentração OsmolarRESUMO
La anafilaxia es una reacción en su mayoría de hipersensibilidad tipo I, que estimula la activación generalizada de mastocitos, y provoca un cuadro clínico multisistémico que puede ser fatal. Se estima que tiene una incidencia de 0,03-0,1% y una prevalencia de vida de 0,5-2% en la población general. Generalmente, la reacción inmunológica ocurre posterior a la ingesta de alimentos, uso de medicamentos o picaduras de insectos, pero también se han descrito mecanismos no inmunológicos (no IgE) que actúan directamente sobre los mastocitos, llamadas en la literatura "reacciones anafilactoideas". La anafilaxia fue descrita por Paul Portier y Charles Robert Richet en 1902 en perros, los cuales desarrollaban esta reacción posterior a la inyección repetida de veneno de anémonas (medusas). Sin embargo, esta entidad no tuvo criterios diagnósticos ni pilares de manejo estructurado hasta el año 2006. En ese año en se publicó el segundo simposio de manejo de la anafilaxia, en donde se definieron criterios diagnósticos clínicos claros y el rol fundamental de la adrenalina en su manejo; la única droga que cambia el pronóstico del paciente.
Anaphylaxis is mainly a type I hypersensitivity reaction. It triggers a widespread activation of mast cells, causing a multisystemic clinical scenario that can be fatal. It is estimated to have an incidence of 0.03-0.1% and a lifetime prevalence of 0.5-2%. Most immunological reactions occur after food ingestion, medication, or insect stings, but non-immunological (non-IgE) mechanisms that act directly on mast cells, called Anaphylactoid Reactions, have been also described. Anaphylaxis was described by Paul Portier and Charles Robert Richet in 1902 in dogs, that developed this disease after repeated injections of anemones (jellyfish) venom. However, this entity didn't have established diagnostic criteria or an standarized management until 2006. In this year, the second anaphylaxis management sym-posium took place and clear clinical diagnostic criteria were defined. The fundamental role of adrenaline in its management was also established. The former is the only drug that has demonstrated to improve prognosis of the patient
RESUMO
A current hypothesis regarding the mechanism of antidepressant (AD) action suggests the involvement of brain-derived neurotrophic factor (BDNF). Consistent with this hypothesis, the receptor for BDNF (and neurotrophin 4/5 (NT-4/5)), Tropomyosin-related kinase B (TrkB), is activated in rodents by treatment with classical AD drugs. Vagal nerve stimulation (VNS), a therapy for treatment resistant depression (TRD), also activates TrkB in rodents. However, the role of this receptor in the therapeutic effects of VNS is unclear. In the current study, the involvement of TrkB in the effects of VNS was investigated in rats using its inhibitor, K252a. Anxiolytic-like and AD-like effects were analyzed using the novelty suppressed feeding test (NSFT) and forced swim test (FST), respectively. K252a blocked the anxiolytic-like effect of chronic VNS treatment and the AD-like effect of acute VNS treatment. By contrast, blocking TrkB did not prevent either the anxiolytic-like or AD-like effect of chronic treatment with desipramine (DMI), a selective noradrenergic reuptake inhibitor; it did, however, block the acute effect of DMI in the FST. To examine whether the activation of TrkB caused by either VNS or DMI is ligand-dependent, use was made of TrkB-Fc, a molecular scavenger for ligands of TrkB. Intraventricular administration of TrkB-Fc blocked the acute activation of TrkB induced by either treatment, indicating that treatment-induced activation of this receptor is ligand-dependent. The behavioral results highlight differences in the involvement of TrkB in the chronic effects of an AD drug and a stimulation therapy as well as its role in acute versus chronic effects of DMI.
Assuntos
Transtornos de Ansiedade/metabolismo , Transtornos de Ansiedade/terapia , Transtorno Depressivo/metabolismo , Transtorno Depressivo/terapia , Receptor trkB/metabolismo , Estimulação do Nervo Vago , Inibidores da Captação Adrenérgica/farmacologia , Animais , Ansiolíticos/farmacologia , Antidepressivos Tricíclicos/farmacologia , Carbazóis/farmacologia , Desipramina/farmacologia , Modelos Animais de Doenças , Inibidores Enzimáticos/farmacologia , Alcaloides Indólicos/farmacologia , Masculino , Atividade Motora/efeitos dos fármacos , Atividade Motora/fisiologia , Fosforilação , Ratos Sprague-Dawley , Receptor trkB/antagonistas & inibidores , Estimulação do Nervo Vago/métodosRESUMO
Mice harboring 1, 2, or 3 copies of the angiotensin-converting enzyme (ACE) gene were used to evaluate the quantitative role of the ACE locus on obesity. Three-copy mice fed with a high-fat diet had lower body weight and peri-epididymal adipose tissue than did 1- and 2-copy mice (P < 0.05). On regular diet, 3-copy mice had to eat more to maintain the same body weight; on a high-fat diet, they ate the same but weighed less than 1- and 2-copy mice (P < 0.05), indicating a higher metabolic rate in 3-copy mice that was not affected by ANG II AT(1) blocker treatment. A catalytically inactive form of thimet oligopeptidase (EC 3.4.24.15; EP24.15) was used to isolate ACE substrates from adipose tissue. Liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) identified 162 peptide peaks; 16 peptides were present in both groups (1- and 3-copy mice fed with a high-fat diet), whereas 58 of the 72 unique peptides were found only in the 3-copy mice. Peptide size distribution was shifted to lower molecular weight in 3-copy mice. Two of the identified peptides, LVVYPWTQRY and VVYPWTQRY, which are ACE substrates, inhibited in vitro protein kinase C phosphorylation in a concentration-dependent manner. In addition, neurolysin (EC 3.4.24.16; EP24.16) activity was lower in fat tissue from 3- vs. 1-copy mice (P < 0.05). Taken together, these results provide evidence that ACE is associated with body weight and peri-epididymal fat accumulation. This response may involve the generation of oligopeptides that inhibit the activity of EP24.16 and other oligopeptidases within the adipose tissue.
Assuntos
Peptidil Dipeptidase A/fisiologia , Tecido Adiposo , Animais , Peso Corporal , Cromatografia Líquida , Relação Dose-Resposta a Droga , Masculino , Metaloendopeptidases/genética , Camundongos , Camundongos Transgênicos , Modelos Estatísticos , Oligopeptídeos/química , Peptídeo Hidrolases/química , Peptídeos/química , Peptidil Dipeptidase A/genética , Fenótipo , Fosforilação , Proteína Quinase C/metabolismo , Fatores de Risco , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
In order to separate, isolate, and determine the number and distribution of the subpopulations of lymphocytes of diverse affinities that are present in an immune response toward a single hapten, anti-trinitrophenyl (TNP) lymphocytes from immunized animals were purified by cell chromatography. Non-adherent spleen cells were passed through a column consisting of TNP-substituted polyacrylamide beads. The retained cells were eluted by applying a linear concentration gradient of TNP-lysine. Elution profiles having a limited number of peaks were obtained in all cases. The avidity of the cells in each fraction was measured by inhibition of formation of immune rosettes by free hapten. Results showed that each peak was located along the gradient according to its affinity since there was a direct correlation between the affinity and the concentration of hapten needed for the elution. The cells in each peak appeared to belong to a homogeneous subpopulation as shown by the slope of the curves obtained in the determination of avidity, suggesting that each peak corresponded to one expanded clone.
Assuntos
Antígenos/imunologia , Separação Celular/métodos , Linfócitos/imunologia , Animais , Cromatografia de Afinidade , Camundongos , Ratos , Ratos Endogâmicos , Formação de Roseta , Soroalbumina Bovina/imunologiaRESUMO
The present work deals with the identification of the ionic currents found in PC12 cells differentiated into neuron-like cells by a 9-11-day cultured-sciatic nerve conditioned medium (CM). PC12 whole-cell currents were measured after chronic exposure to CM. The results obtained in these CM-treated cells reveal that the functional expression of Ca(2+) currents is increased, that Na+ currents are not affected, and that a transient K+ current and a K+ delayed rectifier (K+ dr) current are increased. The combination of nifedipine and omega-conotoxin GVIA (omega-CgTX) does not block completely the increased functional expression of the Ca(2+) current. The remaining current is blocked by omega-agatoxin TK indicating that P/Q-type channels are additionally contributing to the increase in Ca(2+) current. NGF-treated PC12 cells, used as positive controls, confirm that NGF increases the expression of voltage-dependent Na+ currents and of Ca(2+) currents. In addition, we found that NGF also increases a K+ dr-type current in these cells. The results obtained with the CM might be due to a molecule or a mixture of molecules released into the medium by the 9-11-day cultured sciatic nerves.
Assuntos
Diferenciação Celular/efeitos dos fármacos , Meios de Cultivo Condicionados/farmacologia , Canais Iônicos/efeitos dos fármacos , Fatores de Crescimento Neural/farmacologia , Neurônios/efeitos dos fármacos , Células PC12/efeitos dos fármacos , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Canais de Cálcio/efeitos dos fármacos , Canais de Cálcio/metabolismo , Diferenciação Celular/fisiologia , Canais Iônicos/fisiologia , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/fisiologia , Fator de Crescimento Neural/farmacologia , Neurônios/citologia , Neurônios/metabolismo , Células PC12/citologia , Células PC12/metabolismo , Canais de Potássio/efeitos dos fármacos , Canais de Potássio/metabolismo , Ratos , Nervo Isquiático/metabolismo , Canais de Sódio/efeitos dos fármacos , Canais de Sódio/metabolismoRESUMO
The Morris water-maze task was used to evaluate the role of the anteromedial extrastriate visual cortex in the processing of visuospatial information in rats. Six gray male rats received bilateral ibotenic acid injections targeted stereotactically to the rostral part of the anteromedial extrastriate visual cortex. These operated subjects and six other unoperated control rats were tested in the maze. Histological analysis confirmed the localization, symmetry, and depth of lesions in the rostral part of anteromedial area (AMa) in the operated subjects. In these animals, a significantly greater latency to reach the submerged platform was found (U = 0, p = 0.004). The Morris water-maze may be considered as a reference memory task. It presents a stronger demand on the use of allocentric spatial visual cues than on the use of egocentric cues for navigation. Therefore, the present data lend support to the participation of area AMa in the integration of allocentric visuospatial cues or as a link in the memory system involved in the acquisition of this task.
Assuntos
Aprendizagem em Labirinto/fisiologia , Orientação/fisiologia , Percepção Espacial/fisiologia , Córtex Visual/fisiologia , Animais , Sinais (Psicologia) , Masculino , Ratos , Estatísticas não ParamétricasRESUMO
With the aim to evaluate the clinical performance of intrauterine devices (IUDs) especially designed for nulliparous women (TCu 380 Nul and ML Cu 375 sl), a prospective randomized, single-blind study comparing them with standard TCu 380 A, was carried out. We included 1170 healthy nulliparous women randomly allocated to receive any of the three types of IUDs and conducted follow-up for 1 year of use. Continuation and termination rates were evaluated by gross cumulative life table analysis and compared by the log-rank test. Continuation rates (95% confidence interval) at the end of the study for TCu 380 A, TCu 380 Nul and ML Cu 375 sl were 29.5% (+/-12.9), 85.9% (+/-5.3) and 85.4% (+/-5.8), respectively (p < 0.001). There were six pregnancies during the first 3 months of use, for a failure rate of 1% (+/-0.6) in the TCu 380 A group, 0.5% (+/-0.3) in TCu 380 Nul, and no pregnancy in ML Cu 375 sl (p < 0.05). Especially designed IUDs for nulliparous women had a better clinical profile compared with the standard IUD. This may improve the use of IUD in this population.
Assuntos
Dispositivos Intrauterinos de Cobre/estatística & dados numéricos , Paridade , Adulto , Feminino , Humanos , Expulsão de Dispositivo Intrauterino , México , Dor/etiologia , Gravidez , Gravidez não Desejada , Estudos Prospectivos , Método Simples-Cego , Hemorragia Uterina/etiologiaRESUMO
Vulvovaginal candidiasis is a frequent inflammatory process in women but it has not been widely studied in female sex workers (FSWs). To estimate the frequency of Candida species infection in FSWs and to identify related risk factors and clinical findings, we carried out a retrospective study of 1923 FSWs over 11 years. We also performed a prospective study of 163 consecutive FSWs with a history of candidiasis during a 4-year period. Candida species were isolated in 1967 samples (18.5% of the total). Candida albicans (89.3%) was the most frequent species, followed by Candida glabrata (2.7%), Candida parapsilosis (1.2%) and Saccharomyces cerevisiae (0.4%). In the prospective study of 163 patients, we found vaginal discharge in 76.1% of cases, soreness in 52.1% and vulval pruritus in 32.5%. We identified 12 patients (7.4%) with recurrent vulvovaginal candidiasis. No statistical difference was found between recurrent vulvovaginitis and the use of oral contraceptives, oral sex, tight-fitting clothing and synthetic underwear. FSWs have the same prevalence of candidiasis as other groups of women described in published literature. The proportion of albicans and non-albicans species does not differ between women with recurrent and non-recurrent vulvovaginal candidiasis (VVC).
Assuntos
Candidíase Vulvovaginal/epidemiologia , Trabalho Sexual , Adolescente , Adulto , Candidíase Vulvovaginal/microbiologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Estudos Retrospectivos , Fatores de Risco , Parceiros Sexuais , Espanha/epidemiologiaRESUMO
Enzymes responsible for the digestion of food protein by juvenile green abalone (Haliotis fulgens) were studied when fed algae or a sea grass (Phyllospadix torreyi) naturally occurring in the habitat. The effect of food on the composition and activity of the enzymes was also evaluated. Acid, serine proteinases and aminopeptidases, as confirmed by pH profile of activity, specific inhibition and synthetic substrate hydrolysis were found in the digestive organs of juvenile green abalone. Algae and sea grass differentially affected the digestive system in abalone.
Assuntos
Moluscos/enzimologia , Moluscos/fisiologia , Aminopeptidases/química , Aminopeptidases/metabolismo , Fenômenos Fisiológicos da Nutrição Animal , Animais , Ácido Aspártico Endopeptidases/metabolismo , Quimotripsina/farmacologia , Eucariotos/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise , Fatores de Tempo , Tripsina/farmacologiaRESUMO
The present study describes the activity and some characteristics of proteinases in the hepatopancreas of red shrimp Pleoticus muelleri during the different stages of the molting cycle. Proteolytic activity was highest between pH 7.5 and 8. The hepatopancreatic protein content in the premolt stage was higher than in the other stages of the molting cycle (P<0.05). No significant differences were found in total proteolytic activity in the hepatopancreas when comparing molting stages. The proteolytic activity of the P. muelleri hepatopancreas enzyme preparations is the main responsibility of serine proteinases. TLCK, a trypsin inhibitor, reduced azocasein hydrolysis between 26% (intermolt) and 37% (premolt). TPCK, a chymotrypsin inhibitor, did not decrease hydrolytic activity, except for in postmolt. Low trypsin and chymotrypsin activities were found during intermolt, and increased in postmolt. The electrophoretogram of the enzyme extracts shows 12 bands of activity during intermolt (from 16.6 to 53.1 kDa). Some fractions were not detected in the postmolt and premolt stages. Three low molecular weight trypsin forms (17.4, 19.1 and 20 kDa) were found in all molting stages. One band of chymotrypsin (21.9 kDa) was observed in all molting stages. High molecular mass active bands (66-205 kDa) could not be characterized with inhibitors. Comparison of the protease-specific activity of the hepatopancreas of some species indicated a relationship between digestive enzyme activity and feeding habits of the shrimp. Omnivorous shrimp, such as Penaeus vannamei (syn: Litopenaeus vannamei) and Penaeus monodon, showed higher protease activity than the carnivorous shrimp, Penaeus californiensis (syn: Farfantepenaeus californiensis) and P. muelleri. In fact, the enzymatic activity in the hepatopancreas of P. muelleri showed variations in relation to feeding habit and molting cycle.
Assuntos
Decápodes/enzimologia , Decápodes/fisiologia , Sistema Digestório/enzimologia , Endopeptidases/metabolismo , Muda , Animais , Quimotripsina/química , Quimotripsina/metabolismo , Sistema Digestório/efeitos dos fármacos , Endopeptidases/química , Concentração de Íons de Hidrogênio , Peso Molecular , Inibidores de Proteases/farmacologia , Tosilina Clorometil Cetona/farmacologia , Tosilfenilalanil Clorometil Cetona/farmacologia , Tripsina/química , Tripsina/metabolismoRESUMO
Digestive proteinase activities of Artemesia longinaris were assayed at different stages of the molting cycle. Total proteolytic activity in the hepatopancreas was highest during postmolt. Trypsin and chymotrypsin activities were highest during intermolt. Specific inhibitors and zymograms of A. longinaris hepatopancreas extracts showed four trypsins (14.79, 15.49, 16.60, 17.38 kDa, respectively) and three chymotrypsins (21.38, 22.91, 27.54 kDa, respectively). Our results suggest that proteolytic activity in the hepatopancreas of A. longinaris is influenced by the molting cycle. Types and activity of prawn digestive enzymes constitute background information to further study the digestive abilities of these organisms and will lead to understanding their nutritional needs and feeding ecology.
Assuntos
Decápodes/enzimologia , Decápodes/fisiologia , Sistema Digestório/enzimologia , Endopeptidases/metabolismo , Muda/fisiologia , Animais , Quimotripsina/química , Quimotripsina/metabolismo , Endopeptidases/química , Concentração de Íons de Hidrogênio , Inibidores de Proteases/farmacologia , Tripsina/química , Tripsina/metabolismoRESUMO
Trypsin-like enzymes from two morphotypes (here called short and long) of the 'living fossil' Triops of Baja California Sur, Mexico were studied. Adults of both morphotypes were obtained from outdoor static cultures using dry soil from the natural habitats as a source of cysts and culture substrate. Individual and pooled extracts were made from dissected digestive tubes. The effect of pH and temperature on the trypsin activity was studied using N-alpha-benzoyl-DL-Arg-p-nitroanilide (BAPNA) as substrate. The highest proteolytic activity was found at the same pH with extracts of both morphotypes. At this pH, there was greater proteolytic activity at a lower temperature with the short morphotype extract than with the long morphotype extract. Substrate-SDS-PAGE zymograms showed bands of activity. Short morphotype extracts produced six bands; five of them were serine proteases of which three were trypsin-like enzymes. Long morphotype extracts revealed eight bands; six of them were serine proteases of which three were trypsin-like enzymes.
Assuntos
Crustáceos/enzimologia , Tripsina/metabolismo , Animais , Ativação Enzimática , Especificidade por Substrato , Tripsina/isolamento & purificaçãoRESUMO
Several analytical techniques based upon the use of substrate-polyacrylamide gel electrophoresis were evaluated to achieve characterization of aspartate proteases in fish stomach. Since aspartate proteases of fish are more stable at high pH than mammalian pepsins, the most accurate technique for activity assessment is electrophoresis at neutral pH and revealing of such activity at low pH with hemoglobin as substrate. The technique is suitable for characterization of proteases and in comparative assessment of acid protease activity in different sparids.
Assuntos
Ácido Aspártico Endopeptidases/isolamento & purificação , Peixes/metabolismo , Animais , Ácido Aspártico Endopeptidases/análise , Ácido Aspártico Endopeptidases/metabolismo , Eletroforese em Gel de Poliacrilamida , Estabilidade Enzimática , Mucosa Gástrica/enzimologia , Concentração de Íons de Hidrogênio , Perciformes/metabolismo , Especificidade por SubstratoRESUMO
Seed extracts from indigenous and introduced legumes were prepared and used to search for inhibitors of fish muscle proteinases. Fish flesh extracts were prepared from samples of Merluccius productus (Pacific whiting or merluza) obtained off the Oregon coast and in the Gulf of California, respectively. The proteinase activity in the fish muscle for the Pacific whiting was the highest, followed by parasitized merluza. The lowest proteinase activity was for the nonparasitized merluza. Six out of 12 seed extracts reduced the proteinase activity from the fish flesh by more than 50%. The reduction of enzyme activity was higher for samples of fish flesh extracts from the Gulf of California than for the Oregon samples. Seed extracts also reduced the proteinase activity of commercial serine and cysteine proteinases such as trypsin, chymotrypsin, and papain. This inhibitory capacity was maintained even after heating the seed extracts to 90 degrees C for 15 min. Several seed extracts show promise for use as proteinase inhibitors during production of surimi, the intended commercial product of massive fisheries such as Pacific whiting or merluza.
Assuntos
Endopeptidases/metabolismo , Fabaceae/química , Peixes , Músculos/enzimologia , Plantas Medicinais , Inibidores de Proteases/farmacologia , Animais , Peixes/parasitologia , Manipulação de Alimentos/métodos , Músculos/parasitologia , Extratos Vegetais/farmacologia , Sementes/químicaRESUMO
It is presented the case of pulmonary affectation by varicella in a woman with bronchial asthma. The hemoptysis and the multiple pulmonary nodules presence have been the principal manifestations of this entity. As evolution; to emphasize the of the hemoptysis and the radiological normality.
Assuntos
Varicela/diagnóstico , Pneumonia Viral/diagnóstico , Adulto , Asma/complicações , Varicela/complicações , Feminino , Hemoptise/etiologia , Humanos , Pneumonia Viral/complicaçõesRESUMO
The present study aimed to measure the expression of transient receptor potential (TRP) channels in the magnocellular neurones of the paraventricular (PVN) and supraoptic nucleus (SON) in an animal model of hepatic cirrhosis associated with inappropriate vasopressin (AVP) release. In these studies, we used chronic bile duct ligation (BDL) in the rat, which is a commonly used model of hepatic cirrhosis, associated with elevated plasma AVP. The present study tested the hypothesis that changes in TRP vanilloid (TRPV) channel expression may be related to inappropriate AVP release in BDL rats. To test our hypothesis, we utilised laser capture microdissection of AVP neurones in the PVN and SON and western blot analysis from brain punches. Laser capture microdissection and quantitative reverse transcriptase-polymerase chain reaction demonstrated elevated TRPV2 mRNA in the PVN and SON of BDL compared to sham-ligated controls. AVP transcription was also increased as determined using intron specific primers to measure heteronuclear RNA. Immunohistochemistry demonstrated increased AVP and TRPV2 positive cells in both the PVN and SON after BDL. Also, there was an increased co-expression of TRPV2 and AVP cells after BDL. However, there was no change in the colocalisation counts of TRPV2 and oxytocin in both the magnocellular regions evaluated. In the SON but not the PVN, the transcription levels of TRPV4 were also significantly increased in BDL rats. Western blot analysis of punches containing the PVN and SON revealed that TRPV2 protein content was significantly increased in these brain regions in BDL rats compared to sham rats. Our data suggest that regionally specific changes in TRPV expression in the magnocellular neurosecretory cell AVP neurones could alter their osmosensing ability.
Assuntos
Arginina Vasopressina/biossíntese , Regulação da Expressão Gênica/fisiologia , Hiponatremia/metabolismo , Cirrose Hepática Experimental/metabolismo , Núcleo Hipotalâmico Paraventricular/metabolismo , Núcleo Supraóptico/metabolismo , Canais de Cátion TRPV/biossíntese , Animais , Hematócrito , Hiponatremia/complicações , Microdissecção e Captura a Laser/métodos , Cirrose Hepática Experimental/complicações , Masculino , Concentração Osmolar , Ocitocina/biossíntese , Plasma/química , Ratos , Ratos Sprague-DawleyRESUMO
Cathepsin B is a cystein proteinase scarcely studied in crustaceans. Its function has not been clearly described in shrimp species belonging to the sub-order Dendrobranchiata, which includes the white shrimp Litopenaeus vannamei and other species from the Penaeidae family. Studies on vertebrates suggest that these lysosomal enzymes intracellularly hydrolize protein, as other cystein proteinases. However, the expression of the gene encoding the shrimp cathepsin B in the midgut gland was affected by starvation in a similar way as other digestive proteinases which extracellularly hydrolyze food protein. In this study the white shrimp L. vannamei cathepsin B (LvCathB) cDNA was sequenced, and characterized. Its gene expression was evaluated in various shrimp tissues, and changes in the mRNA amounts were compared with those observed on other digestive proteinases from the midgut gland during starvation. By using qRT-PCR it was found that LvCathB is expressed in most shrimp tissues except in pleopods and eye stalk. Changes on LvCathB mRNA during starvation suggest that the enzyme participates during intracellular protein hydrolysis but also, after food ingestion, it participates in hydrolyzing food proteins extracellularly as confirmed by the high activity levels we found in the gastric juice and midgut gland of the white shrimp.