Department of Emergency Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
Neurosci Lett. 2010 Jul 19;479(1):10-2. doi: 10.1016/j.neulet.2010.05.016. Epub 2010 May 12.
Although anesthetic doses of urethane increase plasma levels of ACTH, the exact mechanism through which this occurs is unclear. We theorized that these increases might be a consequence of an increased systemic osmolality owing to the large doses of urethane usually employed. To evaluate this possibility, we measured plasma osmolality and ACTH in a total of six rats after graded infusions of urethane (N=3 rats) or equimolar amounts of mannitol (N=3 rats). Rats received infusions at 15 min intervals up to a cumulative dose equivalent to an anesthetic dose for urethane (1.4 g/kg). Blood samples (0.35 ml) were withdrawn at baseline and 10 min after each infusion. Urethane and mannitol produced significant and equivalent increases in plasma osmolality. However, only urethane evoked increases in plasma ACTH which were maximal (252+/-55 pg/ml from a baseline of 27+/-7 pg/ml) after a cumulative dose of 1 g/kg. Thus, increases in plasma ACTH seen after anesthetic doses of urethane are unlikely to be a consequence of its effect on plasma osmolality.
虽然麻醉剂量的尿烷会增加血浆中的促肾上腺皮质激素（ACTH）水平，但具体的发生机制尚不清楚。我们推测，这些增加可能是由于通常使用的大剂量尿烷导致全身渗透压增加的结果。为了评估这种可能性，我们在总共 6 只大鼠中测量了不同剂量尿烷（N=3 只大鼠）或等摩尔量甘露醇（N=3 只大鼠）输注后的血浆渗透压和 ACTH。大鼠在 15 分钟的间隔内接受输注，直到累积剂量相当于尿烷的麻醉剂量（1.4 g/kg）。在基线和每次输注后 10 分钟采集 0.35 ml 的血样。尿烷和甘露醇均显著增加了血浆渗透压，但只有尿烷引起了血浆 ACTH 的增加，在累积剂量为 1 g/kg 时达到最大值（从基线的 27+/-7 pg/ml 增加到 252+/-55 pg/ml）。因此，麻醉剂量的尿烷引起的血浆 ACTH 增加不太可能是其对血浆渗透压的影响所致。
