第二信使介导模拟低氧下丘脑CRF分泌

SECOND MESSENGERS MEDIAT CRF RELEASING UNDER SIMULATED HYPOXIA

用模拟高原低氧的方法研究急性低氧条件下促肾上腺皮质激素释放因子（ｃｏｒｔｉｃｏｔｒｏｐｉｎ－ｒｅｌｅａｓｉｎｇｆａｃｔｏｒ，ＣＲＦ）分泌的变化及第二信使参与ＣＲＦ分泌的作用。低氧（海拔７ｋｍ）１ｈ后，正中隆起（ｍｅｄｉａｎｅｍｉｎｅｎｃｅ，ＭＥ）处ＣＲＦ含量明显下降（Ｐ＜０．０５），下丘脑（ｈｙｐｏｔｈａｌａｍｕｓ，Ｈｙ）ＣＲＦ（不含ＭＥ）含量无明显变化，而Ｈｙ内ｃＡＭＰ含量明显增加（Ｐ＜０．０１）。脑室注射Ｆｏｒｓｋｌｉｎ、ＴＰＡ后低氧暴露（海拔５ｋｍ）１ｈ，ＭＥＣＲＦ含量下降（Ｐ＜０．０５；Ｐ＜０．０５），ＨｙＣＲＦ无明显变化。脑室注射Ｆｏｒｓｋｌｉｎ后ＨｙｃＡＭＰ含量升高（Ｐ＜０．０５）。脑室注射Ｈ７和ＰＫＡ抑制剂，ＭＥＣＲＦ升高（Ｐ＜０．０５；Ｐ＜０．０１），ＨｙＣＲＦ和ＨｙｃＡＭＰ均无显著变化。上述结果表明急性低氧应激中ＣＲＦ分泌显著增加。

bstract:Using the method of simulated hypoxia and i.c.v. administration we studied the effect of second messenger pathways on CRF secretion under the condition of hypoxia. Exposing at 7000m altitude for 1 hour,CRF content in ME significantly decreased (P<0.05), but that in hypothalamus had no change, at this time cAMP in hypothalalmus increased(P<0.01).When i.c.v. injection of Forsklin or TPA and exposing at 5 000 m altitude for 1 hour CRF in ME declined(P<0.05;P<0.05),that in hypothalamus unchanged, and cAMP in hypothalamus increased. When i.c.v. injection of H7 or PKA inhibitor and exposing at 5 000 m altitude for 1 hour CRF in ME increased(P<0.05;P<0.01), and cAMP in hypothalamus unchanged. These results suggest that during acute hypoxia CRF secretion from hypothalamus increases, second messenger system of PKA and PKC are involved.