Wills-Karp M
Department of Environmental Health Sciences, Johns Hopkins University, School of Hygiene and Public Health, Baltimore, Maryland 21205.
Life Sci. 1991;49(14):1039-45. doi: 10.1016/0024-3205(91)90305-u.
The effects of age on carbachol-stimulated force development and [3H]inositol phosphate production was studied in tracheal rings from guinea pigs aged 1 month and 25 months of age. The pD2 for the contractile response to carbachol was significantly reduced in tracheal tissues from old animals as compared to that of the young tissues (6.49 +/- 0.04, 7.09 +/- 0.04, n = 12), respectively. In contrast, inositol phosphate formation was not altered with increasing age when stimulated by carbachol or NaF, a direct activator of G proteins. Carbachol-induced inositol phosphate accumulation was inhibited by treatment with 1 micrograms/ml pertussis toxin, suggesting that IP1 accumulation is coupled to a pertussis-toxin-sensitive protein. The pD2 values for contraction (7.09 +/- 0.09, 6.49 +/- 0.04) were significantly different from the pD2 values for IP1 accumulation (4.72 +/- 0.14, 5.10 +/- 0.18) in both young and old tissues, respectively. These data suggest that IP1 accumulation is not responsible for the decreased contractile ability in tracheal smooth muscle during aging.
研究了年龄对1月龄和25月龄豚鼠气管环中卡巴胆碱刺激的力量发展和[3H]肌醇磷酸生成的影响。与年轻组织相比，老年动物气管组织对卡巴胆碱收缩反应的pD2显著降低（分别为6.49±0.04、7.09±0.04，n = 12）。相反，当用卡巴胆碱或G蛋白直接激活剂氟化钠刺激时，肌醇磷酸的形成不会随年龄增长而改变。用1微克/毫升百日咳毒素处理可抑制卡巴胆碱诱导的肌醇磷酸积累，这表明IP1积累与一种百日咳毒素敏感蛋白相关。在年轻和老年组织中，收缩的pD2值（7.09±0.09、6.49±0.04）分别与IP1积累的pD2值（4.72±0.14、5.10±0.18）有显著差异。这些数据表明，IP1积累不是衰老过程中气管平滑肌收缩能力下降的原因。
