Functional Properties of Tooth Pulp Neurons Responding to Thermal Stimulation

The response properties of tooth pulp neurons that respond to noxious thermal stimulation of the dental pulp have been not well-studied. The present study was designed to characterize the response properties of tooth pulp neurons to noxious thermal stimulation of the dental pulp. Experiments were conducted on 25 male ferrets, and heat stimulation was applied by a computer-controlled thermode. Only 15% of tooth pulp neurons (n = 39) responded to noxious thermal stimulation of the teeth. Tooth pulp neurons were found in both the superficial and deep nuclear regions of the subnucleus caudalis (Vc) and in the interface between the nucleus caudalis and interpolaris (Vc/Vi). Thirty-seven neurons had cutaneous receptive fields and were classified as either NS (16) or WDR (21) neurons. Repeated heat stimulation of the dental pulp sensitized and increased the number of electrically evoked potentials of tooth pulp neurons. These results provide evidence that both the Vc and Vc/Vi regions contain neurons that respond to noxious thermal stimulation of the dental pulp, and that these cells may contribute to the sensitization process associated with symptomatic pulpitis

Functional Properties of Tooth Pulp Neurons Responding to Thermal Stimulation

The response properties of tooth pulp neurons that respond to noxious thermal stimulation of the dental pulp have been not well-studied. The present study was designed to characterize the response properties of tooth pulp neurons to noxious thermal stimulation of the dental pulp. Experiments were conducted on 25 male ferrets, and heat stimulation was applied by a computer-controlled thermode. Only 15% of tooth pulp neurons (n = 39) responded to noxious thermal stimulation of the teeth. Tooth pulp neurons were found in both the superficial and deep nuclear regions of the subnucleus caudalis (Vc) and in the interface between the nucleus caudalis and interpolaris (Vc/Vi). Thirty-seven neurons had cutaneous receptive fields and were classified as either NS (16) or WDR (21) neurons. Repeated heat stimulation of the dental pulp sensitized and increased the number of electrically evoked potentials of tooth pulp neurons. These results provide evidence that both the Vc and Vc/Vi regions contain neurons that respond to noxious thermal stimulation of the dental pulp, and that these cells may contribute to the sensitization process associated with symptomatic pulpitis

Desempenho animal e produtividade de pastagens tropicais no noroeste do Rio Grande do Sul Animal performance and productivity of tropical pasture in Northwest of Rio Grande do Sul

Avaliou-se a produtividade do capim-elefante anão e do tifton 85 sob pastejo contínuo no noroeste do Rio Grande do Sul, utilizando-se 12 vacas da raça Holandesa, multíparas e com cerca de 100 dias de lactação. Foi aplicada a técnica dos animais reguladores para ajustes da carga animal de forma a manter a oferta de lâminas foliares de 4%. No primeiro ano experimental, o capim-elefante anão e o tifton 85 apresentaram diferenças significativas quanto às taxas médias de acúmulo de lâminas foliares (31,2 vs 22,6kg/ha/dia) e produção animal (17,4 vs 20kg de leite/vaca/dia). No segundo, o tifton 85 foi superior ao capim-elefante anão quanto à taxa de acúmulo de matéria seca de lâminas foliares (38,8 vs 21,9kg/ha/dia), capacidade de suporte (2157 vs 1084kg de peso vivo/ha) e produções por área (70 vs 41,3kg de leite/ha/dia). No segundo ano, em relação ao primeiro, o tifton 85 manteve 88% da capacidade de suporte e 80% da produção por área, enquanto o capim-elefante anão apenas 46% e 56%. A produção média de 17kg de leite/vaca/dia indica um potencial pouco explorado das gramíneas tropicais em sistemas de produção de leite, especialmente na região Sul do Brasil.Productivity of dwarf elephantgrass (Pennisetum purpureum Schum. cv. Mott) and tifton 85 (Cynodon dactylon x Cynodon nlemfuensis) pastures was evaluated under continuous grazing, in the Northwest area of Rio Grande do Sul. Twelve multiparous Holstein cows, at 100 days of lactation were evaluated and the put-and-take technique was used to regulate the stocking rate to maintain 4% of leaf lamina on offer. In the first year, dwarf elephantgrass and tifton 85 were different in leaf accumulation rates (31.2 vs 22.6kg/ha/day) and animal production (17.4 vs 20kg of milk/cow/day). In the second year, tifton 85 had higher leaf accumulation rates (38.8 vs 21.9kg/ha/day), stocking rate (2,157 vs 1,084kg of live weight/ha), and production per area (70 vs 41.3kg of milk/ha/day) than dwarf elephantgrass. Comparing the second to the first years, tifton 85 maintained 88% of stocking rate and 80% of production per area, while dwarf elephantgrass only 46% and 56%, respectively. Average individual production of 17kg of milk/cow/day indicates an unexplored potential of tropical grasses in dairy production systems, especially in the South of Brazil

Animal production and canopy attributes of Cynodon pasture managed under continuous stocking with wethers at three levels of forage allowance

The objective of the present experiment was to evaluate the effect of forage allowance (3, 6 or 9 kg of green leaves dry matter (DM)/100 kg of body weight (BW)) on both animal performance and attributes of Cynodon dactylon var.dactylon canopy managed under continuous stocking by wethers. The study was carried out with 27 Polwarth wethers throughout five 28-day periods, in a completely randomized experiment, which included three paddocks per treatment and three tester animals per paddock. Forage mass varied from 2878 to 6580 kg of DM/ha and was directly related to forage allowance. Leaves proportion (mean of 23%) and leaves growth rate (mean of 25 kg of DM/ha/day) varied between experimental periods in a similar rate for all treatments. Stocking rate varied from 652 to 2428 kg of LW/ha/day and was higher for the lowest forage allowance treatment. Individual BW gain (mean of 9.7 g/day) or gain per area (mean of 406 g/ha/day) were only affected by experimental periods. Forage intake was neither affected by treatments nor by periods (mean of 1042 g of DM/day). Cynodon dactylon var. dactylon pasture may be managed under continuous stocking by grazing wethers at forage allowances varying from 3 to 9 kg of green leaves dry matter/100 kg of BW without effects on canopy attributes or animal production