RESUMO
Aluminum is a neurotoxicant and one of the most harmful metals in the environment; it is producing tissue inflammation and oxidative stress. Curcumin is an effective antioxidant and neuroprotective compound with medicinal potential. Curcumin's effect on AL toxicity was investigated in this study. Two groups of 70 mature adult albino rats were used, each of which was subdivided into five groups: Control, Vehicle, Curcumin, Aluminum, and Curcumin + Aluminum group. For two periods of 20 and 40 days, animal models were administered orally AlCl3 (20 mg kg-1 bw) and/or Curcumin (100 mg kg-1 bw). In the cerebral cortex, aluminum caused a significant rise (p < 0.05) in lipid peroxidation and DNA fragmentation, as well as a significant decrease (p < 0.05) in antioxidant enzymes such as catalase, superoxide dismutase, and glutathione peroxidase. In the brain hippocampus, aluminum caused a major reduction (p < 0.05) in neurotransmitters (dopamine and serotonin), while Acetylcholine esterase activity increased sharply (p < 0.05). Aluminum also triggered histological analyses in the hippocampus of the brain. Curcumin co-administration considerably reduced the increase in lipid peroxidation and DNA fragmentation, but also enhanced the depletion of antioxidant enzymes. Curcumin also reversed the decline in neurotransmitters, the increase in Acetylcholine esterase, and the distortion in the brain hippocampus.(AU)
Assuntos
Animais , Masculino , Ratos Endogâmicos/fisiologia , Curcumina/análise , Antioxidantes , Estresse Oxidativo , Fármacos NeuroprotetoresRESUMO
OFA hr/hr (OFA) rats present a major lactation deficit that impairs offspring survival. To explore whether abnormal stress responsiveness causes this deficit, we compared their hormonal (prolactin, progesterone, and corticosterone) responses to stress (room change and 2-min ether exposure) with those of Wistar and Sprague Dawley (SD) rats. We tested responses during the estrous cycle, pregnancy, lactation, after ovariectomy, and ovarian steroid hormone priming, and responses to suckling. We evaluated hypothalamic expression of receptors for prolactin (PRLRlong) and the isoforms of receptors for progesterone (PRA and B) and estrogen (ERα and ß) in late pregnancy. We tested whether administration of an anxiolytic (diazepam) improved lactation. Ether exposure increased circulating levels of the three hormones in the three strains of rats, cycling and ovariectomized, but was less effective in pregnancy and lactation. Elevated estrogen level (estrus and estradiol-treated ovariectomized rats) potentiated the prolactin response more in SD and OFA rats than in Wistar rats. Elevated progesterone level (late pregnancy, lactation, progesterone-treated ovariectomized rats) inhibited the prolactin response less in OFA than in SD or Wistar rats. Ether exposure inhibited the prolactin and oxytocin responses to suckling only in OFA rats. Diazepam treatment increased pup survival rate and the prolactin response to suckling. Hypothalamic total PR mRNA content, assayed by RT-PCR, was higher in pregnant OFA rats compared with SD and Wistar rats, but the PRB/PRA protein ratio determined by Western blot was lowest in Wistar rats, intermediate in OFA rats, and highest in SD rats. The heightened sensitivity to stress of lactating OFA rats may contribute to their lactational deficit and be caused by a combination of hypoprolactinemia and reduced inhibitory capacity of progesterone.
Assuntos
Lactação/fisiologia , Estresse Fisiológico/fisiologia , Animais , Corticosterona/metabolismo , Diazepam/farmacologia , Estradiol/farmacologia , Receptor alfa de Estrogênio/metabolismo , Receptor beta de Estrogênio/metabolismo , Estro , Éter/farmacologia , Feminino , Lactação/efeitos dos fármacos , Ovariectomia , Ocitocina/metabolismo , Gravidez , Progesterona/metabolismo , Progesterona/farmacologia , Prolactina/metabolismo , Ratos , Ratos Endogâmicos/fisiologia , Ratos Sprague-Dawley , Ratos WistarRESUMO
Avaliamos a responsividade comportamental de ratos machos a odores, tanto de ratos machos quanto de fêmeas. Esses odores foram coletados de várias fontes, como glândulas prepuciais, glândulas da bochecha, porçäo ventral do corpo, urina e fezes. Os machos responsivos foram atraídos por cheiros de machos, principalmente da porçäo ventral do corpo, da urina e das fezes. Os machos näo foram atraídos pelos odores masculinos das glândulas prepuciais e glândulas da bochecha. Além disso, os machos responsivos foram atraídos pelos vários odores das fêmeas. Dentre as cinco fontes odoríferas examinadas, os odores das fezes, urina e porçäo ventral do corpo apresentaram alta significância de atraçäo.
Assuntos
Animais , Masculino , Feminino , Ratos , Fezes , Glândulas Sebáceas , Odorantes , Feromônios/urina , Ratos Endogâmicos/fisiologia , Agressão , Comportamento Sexual Animal , Comportamento Social , Fatores de TempoRESUMO
Los antidepresivos ejercen acciones mixtas sobre los sistemas serotoninérgicos y catecolaminérgicos. Sin embargo, se desconoce si el bloqueo catecolaminérgico impide las acciones de un tricíclico propiedades agonistas serotoninérgicas (clomipramina) en estructuras límbicas. El objetivo del presente estudio es investigar los efectos de una lesión catecolaminérgica en la amíglada basolateral sobre la frecuencia de descarga de neuronas septales laterales e hipocámpicas en ratas tratadas con clomipramina. Una lesión amigdalina con 6-OHDA es similar a las acciones de la colomipramina sobre la frecuencia de descarga en neuronas septales laterales, (ej. aumenta la frecuencia de descarga). Sin embargo, la lesión bloquea además los efectos de la clomipramina en la frecuencia de descarga. La clomipramina disminuye la frecuencia de descarga en neuronas del hipocampo; sin embarago, ni la lesión por 6-OHDA ni el tratamiento con comipramina modificaron la frecuencia de descarga. Se concluye que es necesario, para las acciones de la clompiramina, un sistema amigdaloide catecolaminérgico intacto para el núcleo septal lateral; sin embargo, la acción inicial del tricíclico puede involucrar un bloqueo catecolaminérgico.
Assuntos
Animais , Masculino , Ratos , Região Hipotalâmica Lateral , Clomipramina/efeitos adversos , Núcleos Septais , Ratos Endogâmicos/fisiologiaRESUMO
La administración de la clomipramina a largo plazo, en la rata, aumenta la frecuencia de la descarga en las neuronas septales laterales. Aunque el hipocampo es la principal aferencia para el núcleo septal, se desconoce si la clomipramina aumenta la frecuencia de descarga en la mayoría de las neuronas septohipocámpicas. Así, el presente estudio investiga las acciones de la administración de clomipramina a largo plazo en las neuronas septales laterales identificadas por su relación con el hipocampo. En la mayoría de los registros, la estimulación del hipocampo produce una respuesta excitatoria breve de latencia corta, seguida por un periodo de inhibición de descarga posterior al tratamiento con comipramina. Otras neuronas septales que no responden a la estimulación del hipocamlpo, tampoco responderán al tratamiento con clomipramina. Se concluye que sólo las neuronas septohipocámpicas responden a la clomipramina y que el aumento en la frecuencia de descarga producida por el fármaco es probablemente debida a un proceso de desinhibición mediado por interneuronas.
Assuntos
Animais , Masculino , Ratos , Clomipramina/farmacocinética , Hipocampo/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Núcleos Septais , Ratos Endogâmicos/fisiologiaRESUMO
Los estudios electrofisiológicos sobre neuronas del núcleo supraquiasmático en cortes cerebrales in vitro de la rata, revelan patrones característicos de descarga que han sido previamente clasificados como regulares, irregulares y en estallidos. Se ha encontrado una nueva clase de descarga neuronal, al analizar la distribución entre los intervalos inter-espiga. Basándose en estos resultados se sugiere un nuevo esquema de clasificación. Se propone un modelo que explique la presencia de todos los patrones experimentales. El modelo no sólo infiere la presencia de oscilaciones regulares, sino también sugiere consecuencias interesantes en relación a los componentes del sistema circadiano y su conducta estadística.
Assuntos
Animais , Masculino , Adulto , Ratos , Frequência Cardíaca/fisiologia , Técnicas In Vitro , Neurônios/fisiologia , Núcleos Talâmicos/fisiologia , Ratos Endogâmicos/fisiologia , RatosRESUMO
La mayoría de los mecanismos propuestos para explicar la descarga epiléptica sugieren un excesivo influjo sináptico o posibles cambios en la excitabilidad celular que resultan en una disminución del umbral conculsivo y en la presencia de actividad autosostenida. Es probable que estos cambios sean causados por modificaciones en la sensibilidad de los receptores de membrana a un neurotransmisor específico. En vista de lo anterior, el objetivo del presente estudio ha sido evaluar la sensibilidad del receptor postsináptico por medio de la aplicación microiontoforética de sustancias cuyo efecto farmacológico es bien conocido, para determinar su posible participación en el proceso epiléptico. Se provocaron cambios en la excitabilidad cortical por estimulación eléctrica en la corteza sensoriomotora de ratas anestesiadas con uretano (1 g/kg intraperitoneal), inmovilizadas con bromuro de pancuronio y mantenidas con respiración mecánica. Los estímulos eléctricos consistieron en trenes de pulsos bifásicos, cada uno con duración de un milisegundo con frecuencia de 100 pps y con duración del tren de 1 segundo. La respuesta de la neurona a la acetilcolina fue evaluada antes y después que se establecieron las descargas. La dosis se midió en monoampres de corriente microiontoforética. Los potenciales del campo extracelular se registraron con el barril central de micropipetas. Los barriles periféricos fueron usados para aplicaciones iontoforéticas de acetilcolina (Ach .1, 1M), atropina (25 mM). Uno de estos barriles conteniendo NaCl (2M) se empleó para el paso automático de corriente de balance; para 613 de estas células las descargas ya estaban establecidas; en las restantes 532 células, la corteza fue normal (sin descargas). Un aumento en la frecuencia promedio de descarga celular se obsevó después de la aplicación iontoforética de Ach. Intensidades de 2 a 50 nA de corriente se emplearon en la corteza con descargas establecidas. En la corteza con descargas no establecidad la respuesta celular a la aplicación de Ach fue menor cuando fueron aplicadas corrientes de igual intensidad. En ambas cortezas, las células respondieron con mucha menor intensidad a la aplicación de NaCl con corriente de magnitud similar a la usada para movilizar la Ach. Estos hallazgos muestran un cambio en la excitabilidad celualr que se refleja en un nivel más elevado de respuesta celular cuando la acetilcolina está presente, y sugieren que este neurotransmisor participa en el mecanismo de la epilep
Assuntos
Animais , Masculino , Feminino , Ratos , Anestesia , Epilepsia/fisiopatologia , Técnicas In Vitro , Excitação Neurológica/fisiologia , Plasticidade Neuronal/fisiologia , Pancurônio/administração & dosagem , Ratos Endogâmicos/fisiologia , Receptores Colinérgicos/fisiologia , Receptores de Neurotransmissores/efeitos dos fármacos , Respiração Artificial/instrumentação , Convulsões/fisiopatologia , Uretana/administração & dosagem , Acetilcolina/efeitos adversos , Acetilcolina/análise , Acetilcolina/farmacocinéticaRESUMO
Em uma populaçäo de ratos Wistar, foi avaliado o padräo normal de excreçäo do citrato urinário, sendo observado que: 1) a citratúria normal variou amplamente, de animal para animal; 2) os animais mais idosos (AM > 350) excretaram menos citrato por mg de creatinina (4,7 vs. 7,8 umol de cit/mg de creat) ou citrato/100G PC (12,9 vs. 22,0umol cit/100G) rato do que os ratos mais jovens (AJM); 3) a concentraçäo urinária do citrato, creatinina, cálcio, fósforo, sódio e potássio tiveram correlaçäo linear negativa (p < 0,05) com o volume urinário; 4) a excreçäo do citrato (umol/24h) apresentou correlaçäo positiva (p < 0,05) com a excreçäo de 24 h da creatinina, cálcio, fósforo, sódio e potássio; 5) a concentraçäo e excreçäo urinária do citrato, em ratos Wistar, foi significatemente maior no período diurno (8 às 20hs) vs. período noturno (20 às 8h); 6) a excreçäo do citrato em urina de 24h dos ratos machos adultos jovens (AJM: 7,8 umol cit/mg creat ou 22,0umol cit/100g de rato) foi significantemente maior do que a das fêmeas adultas jovens (AJF: 6,0umol cit/mg creat ou 13,3umol/100g de rato
Assuntos
Humanos , Animais , Masculino , Feminino , Citratos/urina , Ratos Endogâmicos/urina , Fatores Etários , Ratos Endogâmicos/fisiologia , Fatores Sexuais , Fatores de TempoRESUMO
1. The interrelationship between food intake, body weight and oxygen consumption was analysed at 25 degrees C in growing rats. 3. The experiment was divided into two phases lasting four weeks each. During the first phase the animals were subjected to energy restriction and during the second phase they were allowed ad lib energy intake. Four groups of rats were studied: Control with ad lib food intake and three restricted groups R4, R5, and R6 which received during the first phase 4, 5, and 6 g per day of stock diet in a single meal. 3. The results showed a decrease in body weight and oxygen consumption during the restriction period and a recovering of the latter during the refeeding period, without body weight recovering. 4. It is concluded that an energy conservation mechanism is present during food restriction and for some time after refeeding.
Assuntos
Dieta Redutora , Ingestão de Alimentos/fisiologia , Privação de Alimentos/fisiologia , Ratos Endogâmicos/crescimento & desenvolvimento , Envelhecimento , Animais , Peso Corporal/fisiologia , Masculino , Consumo de Oxigênio/fisiologia , Ratos , Ratos Endogâmicos/fisiologia , Fatores de TempoRESUMO
Curarea tecunarum é uma planta usada por tribos indígenas como contraceptivo. As informaçöes etnobotânicas sugerem que o efeito seja no homem, embora a mulher também tome o chá. Com o objetivo de testar, em ratos, a hipótese de que o extrato etanólico de Curarea tecunarum pudesse interromper a produçäo de espermatozóide, projetou-se este trabalho. Ratos Wistar, adultos, foram tratados por gavage com 100 mg (dose única) e 50 mg (por 5 dias ou por 10 dias consecutivos) de extrato etanólico de C. tecunarum (tratado). Um lote de animais recebeu volume equivalente ao extrato, de água destilada (controle A) e outro lote recebeu do mesmo modo, de álcool 50% (controle B). Os animais foram sacrificados aos 7, 21 e 45 dias após o início do tratamento e, imediatamente após o sacrificio foram colhidas amostras de sêmen (ductos deferentes), que foram examinadas para identificar espermatozóides e verificar a sua motilidade. Os seguintes órgäos foram removidos e pesados: hipófise, vesícula seminal (com glândula de coagulaçäo), próstata ventral e testículo (par). Os animais foram pesados no ínicio do tratamento e na data do sacrifício. Näo se observam alteraçöes com significado biológico no peso dos animais dos diferentes grupos. Os órgäos pesados näo mostraram alteraçöes importantes após o tratamento. Todas as amostras de sêmen continham espermatozóides móveis. Embora sejam necessários estudos para avaliar as condiçöes funcionais do espermatozóide (habilidade para fertilizar e gerar embriöes normais) pode-se concluir que, nas condiçöes experimentais deste trabalho, o extrato etanólico de C. tecunarum näo apresenta efeito tóxico sobre o sistema reprodutor e o peso corporal de ratos e näo lesa, severamente, as células germinativas.
Assuntos
Animais , Ratos , Antiespermatogênicos , Espermatogênese , Motilidade dos Espermatozoides , Extratos Vegetais , Plantas Medicinais , Ratos Endogâmicos/fisiologia , Sêmen/efeitos dos fármacos , Bloqueadores de Espermatogênese , Espermatozoides/efeitos dos fármacos , Ducto Deferente/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Brasil , Anticoncepcionais Masculinos , Fertilidade/efeitos dos fármacos , Infertilidade MasculinaRESUMO
The object of this investigation was to study the effect of a benzodiazepine upon the cycle wakefulness-sleep. Wistar rats received 0.9 mg/kg of the chlorate derivative of beta lactam 1.5 benzodiazepine intraperitoneally and the action was analyzed by means of continuous polygraphic registers for ten hours long. Results indicate that this substance decreases wakefulness and slightly increases slow wave sleep. Paradoxical sleep increases significantly (p less than 0.05). Latency of the first phase of paradoxical sleep decreases considerably. These effects suggest that this compound favors sleep under present experimental conditions.
Assuntos
Ansiolíticos/farmacologia , Sono/efeitos dos fármacos , Animais , Benzodiazepinas , Eletromiografia , Eletronistagmografia , Masculino , Relaxamento Muscular/efeitos dos fármacos , Ratos , Ratos Endogâmicos/fisiologia , Sono REM/efeitos dos fármacos , Vigília/efeitos dos fármacosRESUMO
Threshold of stimulation frequency in the perforant path to induce long-term potentiation (LTP) in dentate gyrus was determined in hippocampal slices obtained from two different lines of rats inbred for 30 generations according to their performance in an avoidance escape test in a shuttle box. High-performance (HP) rats were defined as those giving at least 70% conditioned responses (CRs) and low-performance (LP) rats as those giving less than 15% CRs. LTP was defined as a 30% or more increase in the amplitude of the evoked population spike (PS), lasting at least 20 min. Stimulation frequency threshold was determined by stimulating with a train of pulses of 0.5 ms duration during 1 s. The same slice was stimulated with trains of increasing frequency from 5 to 400 Hz, each train separated by an interval of at least 20 min. HP rats showed a lower threshold (13 +/- 4 Hz) than LP rats (92 +/- 42 Hz) for the induction of LTP; there were no differences in the magnitude of LTP. The greater learning ability of HP rats may be related to the plasticity of hippocampal synaptic transmission.
Assuntos
Aprendizagem da Esquiva/fisiologia , Hipocampo/fisiologia , Ratos Endogâmicos/fisiologia , Potenciais de Ação , Animais , Condicionamento Clássico , Estimulação Elétrica , Técnicas In Vitro , Masculino , Memória/fisiologia , RatosRESUMO
A method for estimating the concentration of spermatozoa in the rat cauda epididymidis is described. Treatment of a sperm suspension with 0.05% collagenase for 20-60 min or 0.025% trypsin for 1-2 min at 34-37 degrees C was found to result in consistently homogeneous sperm. Sperm concentration ranged from 152.5 to 230.0 X 10(7) spermatozoa/ml, with a mean of 187.7 (+/- 5.6 SEM) X 10(7) spermatozoa/ml.
Assuntos
Epididimo , Ratos Endogâmicos/fisiologia , Contagem de Espermatozoides/veterinária , Animais , Masculino , Colagenase Microbiana , Ratos , TripsinaAssuntos
Ritmo Circadiano , Distúrbios Nutricionais/fisiopatologia , Ratos Endogâmicos/fisiologia , Fases do Sono , Animais , Caseínas/administração & dosagem , Proteínas Alimentares/administração & dosagem , Feminino , Masculino , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Ratos , Ratos Endogâmicos/embriologia , Ratos Endogâmicos/crescimento & desenvolvimentoRESUMO
Studies were conducted to elucidate the effect of tobacco smoking and marihuana on respiratory functions in both animals and human subjects. The airway resistance (Raw) was measured in apparently healthy Wistar rats using whole body plethysmograph. Histopathological and histochemical observations were also made to ascertain the damage induced by the inhalation of tobacco or marihuana smoke. Various pneometric tests viz. Vital capacity (VC), Functional Residual Capacity (FRC), Residual Volume (RV), Total Lung Capacity (TLC), Forced Expiratory Volume in one second (FEV1.0), Mean Transit Time (MTT), Peak Expiratory Flow Rate (PEFR) and Closing Volume (CV) were carried out in chronic tobacco, marihuana smokers and clinically assessed asthmatic patients. The effect of crude aqueous marihuana extract on specific airway resistance (sRaw) as well as on various pneometric parameters were observed both in animals and human subjects respectively. Animal Studies - inhalation of either marihuana or tobacco smoke significantly increased (p<0.01) airway resistance (Raw), functional residual capacity (FRC) and specific airway resistance (sRaw) as compared to the control rats. Apparent increases in the airway resistance were observed after the first week of exposure but significant differences were only noted in rats exposed for a period of 12 weeks or more. The smoking of either marihuana or tobacco increased the sensitivity of airways to acetylcholine from 18 weeks of exposure onwards. Attempts to elucidate the mechanism of action suggested that the increase in airway responsiveness of alpha adrenoceptors and increased vagal activity which may have resulted in the narrowing of the airways. This has been suggested on the basis of the following observations: i) Intraperitoneal administration of adrenaline (400 ug/kg body weight) following propranolol (2 mg/kg body weight) resulted in an increase in sRaw, whereas a decrease was observed following phentolamine (2 mg/kg body weight). ii) Intramuscular administration of atropine (2 mg.kg body weight) decreased sRaw. Bilateral vagotomy of marihuana or tobacco smoke to exposed rats. iii) The administration of subthreshold concentrations of acetycholine (0.25 ug and 0.5 ug Ach) in 36 weeks smoke exposed rats significantly increased sRaw in contrast to control rats. The administration of atropine prior to acetypcholine in subthreshold concentrations prevented such increase in sRaw in smoke exposed rats indicating the involvement of vagus in inducing the hypersensitivity. The possible existence of bronchitis in marihuana and tobacco smoke to rats from 12 weeks onwards has been further supported by histopathological and histochemical changes which include inter alia catarrhal inflammation resulting in ulceration of the bronchial mucosa, squamous cell metaplasia, increased goblet cell, increased sulphation of mucus, focal alveolitis and alveolar collapse. The interperitoneal administration of 1 ml aqueous crude marihuana extract (1.27 gm/100 ml) significantly decreased the value of sRaw in both marihuana and tobacco smoke exposed rats. This is suggestive of its bronchodilatory effect and has been further demonstrated to be acting through beta adrenoceptors. The cessation of smoking for one month resulted in a decreasing trend of sRaw in rats exposed to either marihuana or tobacco smoke for a period of 36 weeks. This suggests that improvement in the lung picture may be achieved if a longer recovery period is allowed. Human Studies - the comparison of lung functions in chronic marihuana smokers and non-smokers indicated narrowing of both central and peripheral airways as demonstrated by slight decreases in FEV1.0 percent and PEFR and increases in RV/TLC percent, CV/VC percent and CC/TLC percent. These lung functions were found to be more affected in chronic smokers. The bronchodilatory effect observed immediately after smoking a single dose of marihuana to the chronic marihuana smokers may be due to the presence of THC. This bronchodilation was followed by bronchoconstriction when observed after 60 minutes of marihuana smoking. The mechanism of initial bronchodilation is at present unclear but may be due to a direct effect of THC on the bronchial smooth muscle. The bronchoconstrictory effect of marihuana or tobacco smoke is probably due to increased vagal activity and increased responsiveness of alpha adrenoceptors as observed in the animal studies. The presence of a low responsive and a high responsive group of subjects in chronic marihuana smokers has been demonstrated. The high responsive group seems to be more susceptible to marihuana smoke as exemplified by greater decrease in FEV1.0 percent and increase in CV/VC percent. These changes further indicate that the impairment occurs predominantly in the larger airways even though there are signs of onset of small airway disease. The decreases in FEV1.0 percent and PEFR in the asthmatic subjects indicated abnormalities in the larger airways. Significant increases in MTT, CV/VC percent and CC/TLC percent is suggestive of obstruction in the peripheral airways. Administration of 30 mls aqueous extract (200 mg/100 mls) of marihuana to asthmatic subjects resulted in the improvement in lung functions after 30 minutes with the maximum improvement being observed at 60 minutes post administration. The bronchodilatory effect of marijuana extract was quite comparable to a known bronchodilator, ventolin (Salbutamol 200 ug), used in this study. However, the effect of ventolin was faster than aqueous marihuana extract. The bronchodilatory effect of aqueous marihuana extract may be due to the presence of some active ingredients other than THC and may be partly due to the increased activity of beta adrenoceptors (AU)