Cyclic AMP levels in rabbit carotid bodies incubated under control conditions, 100% O2- or 95% O2/5% CO2- equilibrated medium, are close to 1 pmol/mg wet tissue (range 0.4-2.43 pmol/mg). Isobutylmethylxanthine (0.5 mM) increases cyclic AMP levels by a factor of 14 and 8 in HEPES- and CO2/CH3O(-)-buffered medium, respectively. Forskolin (0.5-10 microM) applied during 30 min increases cyclic AMP levels in a dose-dependent manner. Incubation of carotid bodies at low O2 tensions resulted in an elevation of cyclic AMP levels both in the absence and in the presence of isobutymethylxanthine. In the latter conditions cyclic AMP increase was maximum at an O2 tension of 46 mm Hg and tended to decrease at extremely low PO2. In isobutylmethylxanthine-containing Ca2(+)-free medium, cyclic AMP increased linearly with decreasing PO2 from 66 to 13 mm Hg; the absolute cyclic AMP levels attained in Ca2(+)-free medium were smaller than those observed in Ca2(+)-containing medium at any PO2. The differences between Ca2(+)-free and Ca2(+)-containing media appear to be due to the action of released neurotransmitters in the latter conditions, because dopamine and norepinephrine, which are known to be released by hypoxia in a Ca2(+)-dependent manner, increase cyclic AMP in the carotid body. Low pH/high PCO2 and high [K+]e increase cyclic AMP levels only in Ca2(+)-containing medium. Forskolin potentiates the release of catecholamines induced by low PO2. These results suggest that cyclic AMP plays an important role in the modulation of the chemoreception process.

译文

:在对照条件下,100%O2-或95%O2 / 5%CO2平衡的培养基中孵育的兔颈动脉体中的循环AMP水平接近1 pmol / mg湿组织(0.4-2.43 pmol / mg范围)。在HEPES-和CO2 / CH3O(-)缓冲的培养基中,异丁基甲基黄嘌呤(0.5 mM)将循环AMP的水平分别提高14和8倍。在30分钟内施用的Forskolin(0.5-10 microM)以剂量依赖性方式增加循环AMP的水平。在不存在和存在异丁甲基黄嘌呤的情况下,在低O2张力下孵育颈动脉都会导致环AMP含量升高。在后一种情况下,循环AMP的增加在O2张力为46 mm Hg时最大,而在极低的PO2下趋于减少。在不含异丁基甲基黄嘌呤的不含Ca2()的介质中,环状AMP随着PO2从66 mmHg降低到13 mm Hg而线性增加。不含Ca2()的培养基中获得的绝对循环AMP水平要小于任何PO2含Ca2()的培养基中观察到的绝对值。不含Ca2()和含Ca2()的培养基之间的差异似乎是由于后者条件下释放的神经递质的作用所致,因为已知多巴胺和去甲肾上腺素在依赖Ca2()的情况下会通过低氧释放。方式,增加颈动脉体中的循环AMP。低pH /高PCO2和高[K] e仅在含Ca2()的培养基中会增加循环AMP的水平。 Forskolin增强了低PO2诱导的儿茶酚胺释放。这些结果表明,环状AMP在化学感受过程的调节中起重要作用。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录