Substance P is one of the neuropeptide which presents highly in tension site of periodontal ligament during the orthodontic tooth movement. It has been also known as one of the neuropeptides which cause neurogenic inflammation in various tissues and organs. However, there is no report about the effect of substance P on major extracellular matrix protein, collagen production. The purpose of this study was to evaluate the collagen production by substance P in human periodontal ligament cell. The collagenase-digestion method was used to evaluate collagen production and also used Northern blot hybridization for the evaluation of collagen mRNA level. This study also included in terms of prostanglandins and gelatinase production with respect to collagen production. For the collagen degradation, zymography was used to estimate denatured collagen degradation. Dose-dependent effect of substance P on noncollagen protein, collagen, and percent collagen was that substance P increased noncollagen protein synthesis, but decreased collagen sytnsis, So the percent collagen, which determined by relative collagen production against total protein production, was decreased from 7% to 3.6%. This inhibitory effect of substance P on collagen production was disappeared when cells were treated concomitantly with indomethacin. It means that substance P-induced inhibitory effect on collagen production was due at least in part to the production of prostaglandins. To evaluate whether substance P-induced inhibitory effect on collagen production is correspond to the steady-state levels of procollagen mRNA, Northern blot hybridization was performed and it showed that substance P has no effect on the steady-state level of alpha1(I) procollagen mRNA. It means that the inhibitory effect of substance P on collagen production was due to the change of a certain mechanism after posttranscription. In this context, gelatinase production by substance P in periodontal ligament cells was evaluated by zymography. Zyrmogram showed that substance P has no effect on gelatinase production in periodontal ligament cells. To explore whether substance P-induced inhibitory effect on collagen production is selective in periodontal ligament cells or not, MC3T3-E1 cells which originated from mouse calvaria was used. It showed that substance P has no effect on collagen production in MC3T3-E1 cells. Taken together, substance P inhibits collagen production in human periodontal ligament cells. This effect was not due to the change of the steady-state level of procollagen mRNA and gelatinase production, but due at least in part to the change of prostaglandins production.
Animals ; Blotting, Northern ; Collagen* ; Extracellular Matrix ; Gelatinases ; Humans* ; Indomethacin ; Mice ; Neurogenic Inflammation ; Neuropeptides ; Periodontal Ligament* ; Procollagen ; Prostaglandins ; RNA, Messenger ; Skull ; Substance P* ; Tooth Movement

High frequency ventilation (HFV) is a new ventilatory technique that uses very small tidal volume (less than the anatomic dead space) and high frequency, and classified 4 distinct types according to frequency and mode of gas delivery. The mechanism of gas transport of high frequency oscillation ventilation (HFOV) is somewhat different to other types of HFV. To evaluate the determinants of PaCO² in HFOV, a study was done with a HFOV on 9 cats, and the results are: 1) PaCO² was not correlated with frequency at the constant stroke volume (6 voltage) and bias flow (6 L/minutes). 2)PaCO² was correlated with stroke volume but not with bias flow under the constant frequency (15 Hz/min) and bias flow (3 to 6 L/min). From above results, the main determinant of PaCO² on artificial ventilation with HFOV was stroke volume, but further study between flow, the site of delivery to the airway and humidification of bias flow and CO² elimination is required in future research.
Animals ; Bias (Epidemiology) ; Cats* ; High-Frequency Ventilation* ; Stroke Volume ; Tidal Volume ; Ventilation