RESUMO
BACKGROUND: Hindpaw injection of formalin in rodents is used to assess acute persistent pain. The response to formalin is biphasic. The initial response (first minutes) is thought to be linked to inflammatory, peripheral mechanisms, while the latter (around 30 min after the injection), is linked to central mechanisms. This model is useful to analyze the effect of drugs at one or both phases, and the involvement of ion channels in the response. Acid-sensing ion channels (ASICs) regulate synaptic activities and play important roles in pain conditions. Recently, psalmotoxin-1 (Pctx-1), a toxin that inhibits ASIC1a-constituted channels, and antisense ASIC1a-RNA, intrathecal administered in mice were shown to affect both phases of the test. METHODS: The mouse formalin test was performed on C57/BL6 7- to 9-week-old mice. Behavioral tests were conducted and tissue was extracted to detect proteins (ASIC1 and pERK) and ASIC1-mRNA and mir485-5p levels. RESULTS: The injection of formalin was accompanied by an increase in ASIC1 levels. This was detected at the contralateral anterior cingulate cortex (ACC) compared to the ipsilateral side, and both sides of the ACC of vehicle-injected animals. At the spinal cord and dorsal root ganglia, ASIC1 levels followed a gradient stronger at lumbar (L) 3 and decreased towards L5. Gender differences were detected at the ACC; with female mice showing higher ASIC1a levels at the ACC. No significant changes in ASIC1-mRNA levels were detected. Evidence suggests ASIC1 upregulation depends on regulatory microRNAs. CONCLUSION: This work highlights the important role of ASIC1 in pain and the potential role of pharmacological therapies aimed at this channel.
RESUMO
Increase in proton concentration [H+] or decrease in local and global extracellular pH occurs in both physiological and pathological conditions. Acid-sensing ion channels (ASICs), belonging to the ENaC/Deg superfamily, play an important role in signal transduction as proton sensor. ASICs and in particular ASIC1a (one of the six ASICs subunits) which is permeable to Ca2+, are involved in many physiological processes including synaptic plasticity and neurodegenerative diseases. Activity-dependent long-term potentiation (LTP) is a major type of long-lasting synaptic plasticity in the CNS, associated with learning, memory, development, fear and persistent pain. Neurons in the anterior cingulate cortex (ACC) play critical roles in pain perception and chronic pain and express ASIC1a channels. During synaptic transmission, acidification of the synaptic cleft presumably due to the co-release of neurotransmitter and H+ from synaptic vesicles activates postsynaptic ASIC1a channels in ACC of mice. This generates ASIC1a synaptic currents that add to the glutamatergic excitatory postsynaptic currents (EPSCs). Here we report that modulators like histamine and corticosterone, acting through ASIC1a regulate synaptic plasticity, reducing the threshold for LTP induction of glutamatergic EPSCs. Our findings suggest a new role for ASIC1a mediating the neuromodulator action of histamine and corticosterone regulating specific forms of synaptic plasticity in the mouse ACC.
Assuntos
Canais Iônicos Sensíveis a Ácido , Potenciação de Longa Duração , Canais Iônicos Sensíveis a Ácido/metabolismo , Animais , Corticosterona , Giro do Cíngulo/metabolismo , Histamina , CamundongosRESUMO
This study aimed to evaluate renal morphology and the renal renin-angiotensin system in 6- and 81-day-old male and female offspring exposed to zinc deficiency during fetal life, lactation and/or postnatal growth. Female Wistar rats were fed low- or control zinc diets from pregnancy to offspring weaning. Afterwards, offspring were fed a low- or a control zinc diet until 81 days of life. In 6- and/or 81-day-old offspring, we evaluated systolic blood pressure, renal morphology, renal angiotensin II and angiotensin 1-7 concentration, and AT1 and AT2 receptors and angiotensin-converting enzymes protein and/or mRNA expression. At 6 days, zinc-deficient male offspring showed decreased glomerular filtration areas, remodelling of renal arteries, greater number of renal apoptotic cells, increased levels of Angiotensin II, higher Angiotensin II/Angiotensin 1-7 ratio and increased angiotensin-converting enzyme 1, AT1 and AT2 receptors mRNA and/or protein expression. Exacerbation of the renal Ang II/AT1 receptor axis and remodelling of renal arteries were also observed in adult zinc-deficient male offspring. An adequate zinc diet during post-weaning life did not improve all the alterations induced by zinc deficiency in early stages of development. Female offspring would appear to be less sensitive to zinc deficiency with no increase in blood pressure or significant alterations in renal morphology and the renin-angiotensin system. Moderate zinc deficiency during critical periods of prenatal and postnatal development leads to early morphological renal alterations and to permanent and long-term changes in the renal renin-angiotensin system that could predispose to renal and cardiovascular diseases in adult life.
Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Rim/metabolismo , Fenômenos Fisiológicos da Nutrição Materna , Sistema Renina-Angiotensina , Zinco/deficiência , Angiotensina II/sangue , Angiotensinas/metabolismo , Animais , Pressão Sanguínea , Dieta , Feminino , Feto/metabolismo , Humanos , Rim/patologia , Lactação/metabolismo , Masculino , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Ratos , Ratos Wistar , Caracteres Sexuais , Zinco/administração & dosagemRESUMO
Acid-sensing ion channels (ASICs) regulate synaptic activities and play important roles in neurodegenerative diseases. It has been reported that homomeric ASIC-1a channels are expressed in neurons of the medial nucleus of the trapezoid body (MNTB) of the auditory system in the CNS. During synaptic transmission, acidification of the synaptic cleft presumably due to the co-release of neurotransmitter and H+ from synaptic vesicles activates postsynaptic ASIC-1a channels in mice up to 3 weeks old. This generates synaptic currents (ASIC1a-SCs) that add to the glutamatergic excitatory postsynaptic currents (EPSCs). Here we report that neuromodulators like histamine and natural products like lactate and spermine potentiate ASIC1a-SCs in an additive form such that excitatory ASIC synaptic currents as well as the associated calcium influx become significantly large and physiologically relevant. We show that ASIC1a-SCs enhanced by endogenous neuromodulators are capable of supporting synaptic transmission in the absence of glutamatergic EPSCs. Furthermore, at high frequency stimulation (HFS), ASIC1a-SCs contribute to diminish short term depression (STD) and their contribution is even more relevant at early stages of development. Since ASIC channels are present in almost all types of neurons and synaptic vesicles content is acid, the participation of protons in synaptic transmission and its potentiation by endogenous substances could be a general phenomenon across the central nervous system. This article is part of a Special Issue entitled: Honoring Ricardo Miledi - outstanding neuroscientist of XX-XXI centuries.
Assuntos
Canais Iônicos Sensíveis a Ácido , Transmissão Sináptica , Canais Iônicos Sensíveis a Ácido/metabolismo , Animais , Cálcio/metabolismo , Camundongos , Neurônios/metabolismo , Sinapses/metabolismoRESUMO
OBJECTIVE: Intrauterine and postnatal micronutrient malnutrition may program metabolic diseases in adulthood. We examined whether moderate zinc restriction in male and female rats throughout fetal life, lactation, or postweaning growth induces alterations in liver, adipose tissue, and intermediate metabolism. METHODS: Female Wistar rats were fed low-zinc or control zinc diets from pregnancy to offspring weaning. After weaning, male and female offspring were fed either a low-zinc or a control zinc diet. At 74 d of life, oral glucose tolerance tests were performed and serum metabolic profiles were evaluated. Systolic blood pressure and oxidative stress and morphology of liver and retroperitoneal adipose tissue were evaluated in 81 d old offspring. RESULTS: Zinc restriction during prenatal and postnatal life induced an increase in systolic blood pressure, hyperglycemia, hypertriglyceridemia, higher serum glucose levels at 180 min after glucose overload, and greater insulin resistance indexes in male rats. Hepatic histologic studies revealed no morphologic alterations, but an increase in lipid peroxidation and catalase activity were identified in zinc-deficient male rats. Adipose tissue from zinc-deficient male rats had adipocyte hypertrophy, an increase in lipid peroxidation, and a reduction in catalase and glutathione peroxidase activity. Adequate dietary zinc content during postweaning growth reversed basal hyperglycemia, hypertriglyceridemia, insulin resistance indexes, hepatic oxidative stress, and adipocyte hypertrophy. Female rats were less sensitive to the metabolic effects of zinc restriction. CONCLUSIONS: This study strengthens the importance of a balanced intake of zinc during growth to ensure adequate lipid and carbohydrate metabolism in adult life.
Assuntos
Exposição Materna/efeitos adversos , Doenças Metabólicas/metabolismo , Complicações na Gravidez/metabolismo , Efeitos Tardios da Exposição Pré-Natal/metabolismo , Zinco/deficiência , Animais , Suplementos Nutricionais , Feminino , Feto/metabolismo , Lactação/metabolismo , Masculino , Fenômenos Fisiológicos da Nutrição Materna , Doenças Metabólicas/etiologia , Gravidez , Complicações na Gravidez/etiologia , Efeitos Tardios da Exposição Pré-Natal/etiologia , Ratos , Ratos Wistar , Fatores Sexuais , Desmame , Zinco/administração & dosagemRESUMO
Micronutrient malnutrition during intrauterine and postnatal growth may program cardiovascular diseases in adulthood. We examined whether moderate zinc restriction in male and female rats throughout fetal life, lactation and/or postweaning growth induces alterations that can predispose to the onset of vascular dysfunction in adulthood. Female Wistar rats were fed low- or control zinc diets from pregnancy to offspring weaning. After weaning, offspring were fed either a low- or a control zinc diet until 81 days. We evaluated systolic blood pressure (SBP), thoracic aorta morphology, nitric oxide (NO) system and vascular reactivity in 6- and/or 81-day-old offspring. At day 6, zinc-deficient male and female offspring showed a decrease in aortic NO synthase (NOS) activity accompanied by an increase in oxidative stress. Zinc-deficient 81-day-old male rats exhibited an increase in collagen deposition in tunica media, as well as lower activity of endothelial NOS (eNOS) that could not be reversed with an adequate zinc diet during postweaning life. Zinc deficiency programmed a reduction in eNOS protein expression and higher SBP only in males. Adult zinc-deficient rats of both sexes showed reduced vasodilator response dependent on eNOS activity and impaired aortic vasoconstrictor response to angiotensin-II associated with alterations in intracellular calcium mobilization. Female rats were less sensitive to the effects of zinc deficiency and exhibited higher eNOS activity and/or expression than males, without alterations in SBP or aortic histology. This work strengthens the importance of a balanced intake of micronutrients during perinatal growth to ensure adequate vascular function in adult life.
Assuntos
Fenômenos Fisiológicos da Nutrição Animal , Desnutrição/complicações , Fenômenos Fisiológicos da Nutrição Materna , Prenhez , Doenças Vasculares/etiologia , Zinco/deficiência , Acetilcolina/química , Angiotensina II/química , Ração Animal , Animais , Aorta Torácica/metabolismo , Aorta Torácica/patologia , Cálcio/metabolismo , Feminino , Lactação , Masculino , Micronutrientes , NG-Nitroarginina Metil Éster/química , Óxido Nítrico/química , Óxido Nítrico Sintase/metabolismo , Nitroprussiato/química , Oxidantes/química , Estresse Oxidativo , Gravidez , Ratos , Ratos Wistar , Sístole , Doenças Vasculares/fisiopatologia , Vasoconstritores/química , Zinco/sangueRESUMO
PURPOSE: Zinc restriction during fetal and postnatal development could program cardiovascular diseases in adulthood. The aim of this study was to determine the effects of zinc restriction during fetal life, lactation, and/or post-weaning growth on cardiac inflammation, apoptosis, oxidative stress, and nitric oxide system of male and female adult rats. METHODS: Wistar rats were fed a low- or a control zinc diet during pregnancy and up to weaning. Afterward, offspring were fed either a low- or a control zinc diet until 81 days of life. IL-6 and TNF-α levels, TUNEL assay, TGF-ß1 expression, thiobarbituric acid-reactive substances that determine lipoperoxidation damage, NADPH oxidase-dependent superoxide anion production, antioxidant and nitric oxide synthase activity, mRNA and protein expression of endothelial nitric oxide synthase, and serine1177 phosphorylation isoform were determined in left ventricle. RESULTS: Zinc deficiency activated apoptotic and inflammatory processes and decreased TGF-ß1 expression and nitric oxide synthase activity in cardiac tissue of both sexes. Male zinc-deficient rats showed no changes in endothelial nitric oxide synthase expression, but a lower serine1177 phosphorylation. Zinc deficiency induced an increase in antioxidant enzymes activity and no differences in lipoperoxidation products levels in males. Females were less sensitive to this deficiency exhibiting lower increase in apoptosis, lower decrease in expression of TGF-ß1, and higher antioxidant and nitric oxide enzymes activities. A zinc-adequate diet during postnatal life reversed most of these mechanisms. CONCLUSION: Prenatal and postnatal zinc deficiency induces alterations in cardiac apoptotic, inflammatory, oxidative, and nitric oxide pathways that could predispose the onset of cardiovascular diseases in adult life.
Assuntos
Deficiências Nutricionais/fisiopatologia , Desenvolvimento Fetal , Lactação , Fenômenos Fisiológicos da Nutrição Materna , Miocardite/etiologia , Estresse Oxidativo , Zinco/deficiência , Animais , Apoptose , Biomarcadores/sangue , Biomarcadores/metabolismo , Vasos Coronários/imunologia , Vasos Coronários/metabolismo , Vasos Coronários/patologia , Vasos Coronários/fisiopatologia , Deficiências Nutricionais/imunologia , Deficiências Nutricionais/metabolismo , Deficiências Nutricionais/patologia , Endotélio Vascular/imunologia , Endotélio Vascular/metabolismo , Endotélio Vascular/patologia , Endotélio Vascular/fisiopatologia , Feminino , Regulação Enzimológica da Expressão Gênica , Mediadores da Inflamação/sangue , Mediadores da Inflamação/metabolismo , Masculino , Miométrio/imunologia , Miométrio/metabolismo , Miométrio/patologia , Miométrio/fisiopatologia , Óxido Nítrico Sintase Tipo III/genética , Óxido Nítrico Sintase Tipo III/metabolismo , Gravidez , Distribuição Aleatória , Ratos Wistar , DesmameRESUMO
The aim of this study was to evaluate whether moderate zinc restriction in rats throughout fetal life, lactation, and/or postweaning growth results in early changes in cardiac morphology predisposing the onset of cardiac dysfunction in adult life as well as sex-related differences in the adaptation to this nutritional injury. Female Wistar rats received low or control zinc diets from the beginning of pregnancy up to offspring weaning. After being weaned, offspring were fed either a low or control zinc diet until 81 days. Systolic blood pressure was measured. Echocardiographic and electrocardiographic examinations, morphological experiments, and apoptosis by TUNEL assay were performed in the left ventricle. In the early stages, zinc-deficient male and female offspring showed an increase in cardiomyocyte diameter, probably associated with an increase in cardiac apoptotic cells, but smaller myocyte diameters in adulthood. In adult males, this nutritional injury induced decreased contractility and dilatation of the left ventricle, not allowing the heart to compensate the higher levels of blood pressure, and hypertrophic remodeling of coronary arteries associated with increased blood pressure. Adequate zinc intake during postweaning life did not overcome blood pressure levels but reversed some of the detrimental effects of earlier zinc deficiency in cardiac morphology and function. Females were less sensitive to this deficiency, exhibiting normal levels of blood pressure and no structural or functional heart alterations in adult life. The present study demonstrates that the effects of zinc deficiency on blood pressure, cardiac morphology, and function differ between sexes, with males more predisposed to develop cardiovascular diseases in adulthood.