Kosik-Bogacka D, Tyrakowski T
Department of Biology and Medical Parasitology, Pomeranian Medical University, Szczecin, Poland.
J Physiol Pharmacol. 2004 Jul;55 Suppl 2:117-28.
The aim of this study was to investigate the effect of aging on sodium and chloride ions transport in the isolated rabbit caecum. The experiment consisted in measuring PD- transepithelial electrical potential difference mV SM-mechanical stimulation and mechano-sensitivity (dPD) in collected from 12- and 36-month-old rabbits. A modified Ussing system was used for the experiment. Under the incubation in Ringer solution the values of PD and dPD of young rabbit caecum were, respectively, -3.0 +/-0.4 mV and -1.2 +/-0.3 mV. In 36-month rabbits, on the other hand, the values of these parameters were lower, PD by about 90% whereas dPD by about 83%. Incubation of young rabbits caecum with the presence of amiloride resulted in a reduction of PD by about 17 % and dPD by about 50%, while it did not influence the electrophysiological parameters of caecum in 36-month rabbits. Incubation with bumetanide on young rabbits caecum resulted in PD dropped by about 70% and dPD by about 83%. In the same incubation conditions as those applied for incubation of 36-month rabbits caecum, the level of PD decreased by about 67% while dPD by about 50%. Incubation of young rabbits caecum at the presence of both transport inhibitors resulted in PD decreased by about 87% and dPD by about 83%, whereas that applied for the old rabbits' caecum reduced PD by about 90%, without influencing dPD. Presented data demonstrate that the process of organism ageing inhibits sodium ion transport as well as reduces caecum epithelium sensitivity to mechanical stimuli. Probably, it is a consequence of a reduced with age release of neurotransmitter from sensory terminals; these neurotransmitters modify transepithelial ion transport.
本研究的目的是探讨衰老对离体兔盲肠中钠和氯离子转运的影响。实验包括测量12月龄和36月龄兔子的PD（跨上皮电位差，单位为mV）、SM（机械刺激）和机械敏感性（dPD）。实验采用改良的Ussing系统。在林格氏液中孵育时，幼兔盲肠的PD和dPD值分别为-3.0±0.4 mV和-1.2±0.3 mV。另一方面，在36月龄的兔子中，这些参数的值较低，PD降低约90%，而dPD降低约83%。用氨氯吡咪孵育幼兔盲肠导致PD降低约17%，dPD降低约50%，而对36月龄兔子盲肠的电生理参数没有影响。用布美他尼孵育幼兔盲肠导致PD下降约70%，dPD下降约83%。在与36月龄兔子盲肠孵育相同的条件下，PD水平下降约67%，而dPD下降约50%。在两种转运抑制剂存在的情况下孵育幼兔盲肠导致PD下降约87%，dPD下降约83%，而对老年兔子盲肠的孵育使PD降低约90%，但不影响dPD。所呈现的数据表明，机体衰老过程会抑制钠离子转运，并降低盲肠上皮对机械刺激的敏感性。这可能是由于感觉末梢神经递质随年龄增长释放减少所致；这些神经递质可改变跨上皮离子转运。
