Temporal and spatial appearance of the membrane cytoskeleton and perineuronal nets in the rat neocortex.

Parvalbumin-immunoreactive interneurons are surrounded by perineuronal nets, containing molecules of the extracellular matrix (e.g. tenascin-R). Furthermore, they seem to have a special cytoskeleton composed of, among others, ankyrinR and beta Rspectrin. In the present developmental study we showed that the intracellular markers parvalbumin, ankyrinR and beta Rspectrin as well as Vicia Villosa agglutinin, an extracellular marker for perineuronal nets, appeared in the second postnatal week. In the third postnatal week, ankyrinR and beta R spectrin were present in the parvalbumin-positive interneurons. Tenascin-R appeared in a similar topographic distribution as the intracellular markers. The adult pattern was established upon the end of the fourth postnatal week. Our results indicate that cytoskeletal maturity maybe a prerequisite for the organization of perineuronal nets of extracellular matrix.

Efeito da heparina sódica e da enoxaparina na consolidação de fratura da tíbia no rato: avaliação clínica e anatomopatológica e biomecânica

Foi realizado estudo experimental em ratos para avaliar o efeito do anticoagulante na consolidação óssea, conforme critérios clínicos, anatomopatológicos e biomecânicos. Manualmente, após perfuração do osso, foi produzida fratura aberta, na diáfise da tíbia direita, mantida sem imobilização, em 72 ratos machos da linhagem Wistar, com 60 dias de idade e peso médio de 242 gramas. Doze horas após a fratura, foi iniciado tratamento anticoagulante, mantido por 28 dias. Via subcutânea, um grupo recebeu heparina sódica na dose de 200UI/Kg de 12 em 12 horas, enquanto outro, recebeu enoxaparina na dose de 1mg/Kg de 12 em 12 horas, doses preconizadas para tratamento do tromboembolismo em humanos. O terceiro grupo, controle, recebeu água destilada. Durante o experimento, os animais foram avaliados clinicamente e após 28 dias, sacrificados. Nos animais dos três grupos, a evolução clínica foi semelhante. Mediante análise anatomopatológica efetuada por estudo descritivo e quantitativo, foi observada presença de fibrose, cartilagem e osso igualmente nos três grupos, sempre com predomínio de tecido ósseo. O estudo biomecânico, realizado por intermédio de ensaios de flexão, demonstrou coeficiente de rigidez e carga máxima semelhantes nos três grupos. Nenhuma diferença clínica, anatomopatológica e biomecânica foi encontrada, resultando todas as fraturas em consolidação de acordo com os critérios adotados, concluindo-se, portanto, que a heparina sódica e a enoxaparina nas doses, via e tempo de administração utilizados não interfiriram na consolidação da fratura da tíbia do rato.

Endogenous corticosteroids and insulin in acute inflammation

Carrageenin-induced inflammatory responses in the hindpaws of rats were quantitated by measuring: (1) alterations in volumes of the paws; and (2) alterations in concentration of dye, previously injected intravenously, which was recovered in perfusates from the paws. The inflammatory response in one paw was attenuated by previously inducing an inflammatory response in the contralateral paw. The effect was abolished by pretreatment with insulin. Indexes of adrenal activity were increased after the induction of the inflammatory response and they were not attenuated by pretreatment with insulin. Adrenal hyperactivity was characterized by increased serum corticosterone concentration, decreased adrenal ascorbic acid content, and reduced number of circulating eosinophils. It is concluded that inflammatory stimuli which lead to alterations in microvessels depend on a facilitatory effect of insulin. This effect is antagonized by glucocorticoids released in enhanced concentrations after the application of noxious stimuli. Therefore, endogenous insulin and glucocorticoids act as modulators of inflammatory responses.

Treatment of rat nephrotoxic nephritis. Use of 5-fluorouracil or methotrexate-5-fluorouracil association

To evaluate the effect of 5-fluorouracil (F) and methotrexate-5-fluorouracil association (MTX-F) on nephrotoxic nephritis, seven groups of 10 rats were inoculated with anti-rat glomerular basement membrane serum (AGBMS); five groups were treated with different doses of F, beginning on the 2nd or the 6th day, one group with MTX-F beginning on the 2nd day and one group (control) with distilled water. Twenty-four hour proteinuria was determined weekly until the 71st day. The kidneys were examined histologically and by immunofluorescence. The group treated with F (1.3 mg/100 g body weight) developed a severe glomerulonephritis similar to the control group; (b) the groups treated with F (2.0 mg/100 g body weight) or with MTX-F showed progressively lower proteinuria, less severe histological changes and less intense fluorescence due to autologous antibodies. The best results were observed in the MTX-F group and in the F group treated from the 6th day. These groups presented at the 71st day proteinuria of 84 and 91 mg as compared to 312 mg in the control group, and minimal histological lesions as compared to glomerulosclerosis and tubular atrophy in the control group. We concluded that either F or MTX-F produced significant improvement of nephrotoxic nephritis due to inhibition of autologous antibody production.

Pressure evaluation of the antireflux ability of the rat ureterovesical junction

The bladder pressure necessary to cause vesicoureteral reflux (VUR) was measured in 16 female rats. Under general anesthesia, the ureters were exposed via an abdominal incission and a pressure catheter was placed near the uterovesical junction. Values of bladder distension and bladder pressure increase to cause VUR were obtained by injecting isotonic saline in one ureter until VUR in the opposite ureter was detected as a sudden pressure increase. After 5 min the same procedure was done on the contralateral side. This procedure was repeated eight times in each rat with a 15-min intermission. The bladder pressure at which VUR occurred was measured through a uretral catheter. Two groups were studied: G1, control, and G2, administration of intravenous metoclopramide (0.007 mg/100 g body weight) four times.

Effect of alcohol on the rat juxtaprostatic pelvic ganglia and gonads.

In the present paper, it was investigated the aspect of the intrapelvic autonomic neuronal system (juxtaprostatic ganglion) and gonads of rats submitted to a experimental alcoholism. The animals which had water substituted for 35% sugar cane spirit for 30 d, presented testicular lesions as well as numeric and degenerative alterations in the juxtaprostatic pelvic ganglia neurons.

Autoradiographic investigation of effects of high-dose colchicine on dentinogenesis in rat incisors

Twelve female Wistar rats received 1.5 mg/kg of colchicine (CLC) intravenously. Control animals were similarly injected with isotonic saline solution. The animals were killed 5 h, 24 h, 3 days and 7 days after injection. Ninety minutes prior to sacrifice, all animals received an intraperitoneal injection of 3H-proline. Autoradiograms of maxillary incisors showed that CLC increased the retention of the labeled precursor in the odontoblasts. It was also shown that the odontoblasts in the different sectors of the rat incisor present different sensitivities to the CLC action.

Natriuresis induced by cholinergic stimulation of the locus coeruleus in the rat

Carbachol injected into the locus coeruleus (LC) induced a dose-dependent natriuresis in the rat. This natriuresis was maintained above control levels during the 120 min of urine sampling. Seizures and arterial blood pressure increase were also observed but they disappeared within 20 min after carbachol injection. Natriuresis was not obtained with either injections of carbachol outside the LC or with hypertonic solutions injected into the LC. Injection of atropine into the LC blocked the natriuresis induced by carbachol. In summary, our data show that carbachol induces natriuresis by an action on muscarinic receptors located in the LC region. © 1990.