Carvounis C P, Schroeder E T, Cushley P, Hueber P, Patchin D
Section of Nephrology, Veterans Administration Medical Center, Syracuse, New York.
Am J Physiol. 1988 Oct;255(4 Pt 2):F685-9. doi: 10.1152/ajprenal.1988.255.4.F685.
Addition of histidine to the serosal bath of the toad bladder increases the hydrosmotic response of vasopressin in this tissue. Because this represents primarily the effect of the imidazole ring of histidine, which is a known inhibitor of the production of prostaglandins, we evaluated whether histidine increases the response to vasopressin through decreased prostaglandin production. Histidine increases the response to vasopressin much more than 10(-5) M naproxen, even though the latter was equipotent to histidine in reducing prostaglandin E2 (PGE2) production. Furthermore, histidine was additive to naproxen in increasing the hydrosmotic effect of vasopressin, without causing a further decrease in PGE2 production. These findings suggest that histidine has an effect over and above that due to inhibition of prostaglandin synthesis. Our results suggest that histidine enhances the permeability of the tissue beneath the luminal membrane, an effect not found with naproxen. We propose that histidine increases the hydrosmotic response to vasopressin through at least two distinct mechanisms: 1) it decreases prostaglandin synthesis and thus increases luminal permeability; 2) it decreases the resistance to water movement of the tissues beneath the luminal membrane.
在蟾蜍膀胱的浆膜浴中添加组氨酸可增强该组织中血管加压素的渗透反应。由于这主要代表了组氨酸咪唑环的作用，而咪唑环是一种已知的前列腺素生成抑制剂，因此我们评估了组氨酸是否通过减少前列腺素生成来增强对血管加压素的反应。组氨酸比10(-5)M萘普生更能增强对血管加压素的反应，尽管后者在减少前列腺素E2（PGE2）生成方面与组氨酸等效。此外，在增强血管加压素的渗透作用方面，组氨酸与萘普生具有相加作用，且不会导致PGE2生成的进一步减少。这些发现表明，组氨酸除了抑制前列腺素合成外还有其他作用。我们的结果表明，组氨酸可增强腔面膜下方组织的通透性，而萘普生则无此作用。我们提出，组氨酸至少通过两种不同机制增强对血管加压素的渗透反应：1）它减少前列腺素合成，从而增加腔面通透性；2）它降低腔面膜下方组织对水移动的阻力。
