Holmes M C, Antoni F A, Catt K J, Aguilera G
Neuroendocrinology. 1986;43(2):245-51. doi: 10.1159/000124533.
In an in vitro system, we have demonstrated concomitant release of corticotropin-releasing factor (CRF) and arginine vasopressin (AVP) from the median eminence (ME) of normal and adrenalectomized rats. The ME were incubated in a Krebs-Ringer bicarbonate medium, CRF and AVP released into the medium were measured by radioimmunoassay. The release of both neuropeptides was stimulated by increasing concentrations of potassium (28-56 mM) in the incubation medium, or by addition of veratridine (5-20 microM). In both cases the release process was dependent on the presence of calcium in the incubation medium. Interestingly, potassium-induced release was found to be relatively insensitive to calcium channel antagonists that are potent inhibitors in smooth and cardiac muscle. The sodium channel antagonist, tetrodotoxin (1 microM), completely blocked the effect of veratridine, while no change was seen in the response to potassium. Adrenalectomy increased the ratio of AVP:CRF release from 2:1 in ME removed from sham-operated rats to 8:1 in ME from the adrenalectomized group. We suggest that this ratio of AVP:CRF release may also pertain in vivo, and that AVP could be the predominant corticotropic stimulus in adrenalectomized rats.
在体外系统中，我们已证明正常大鼠和肾上腺切除大鼠的正中隆起（ME）可同时释放促肾上腺皮质激素释放因子（CRF）和精氨酸加压素（AVP）。将ME置于 Krebs-Ringer 碳酸氢盐培养基中孵育，采用放射免疫分析法测定释放到培养基中的CRF和AVP。通过增加孵育培养基中钾的浓度（28 - 56 mM）或添加藜芦碱（5 - 20 μM）来刺激这两种神经肽的释放。在这两种情况下，释放过程均依赖于孵育培养基中钙的存在。有趣的是，发现钾诱导的释放对钙通道拮抗剂相对不敏感，而钙通道拮抗剂在平滑肌和心肌中是有效的抑制剂。钠通道拮抗剂河豚毒素（1 μM）完全阻断了藜芦碱的作用，而对钾的反应未见变化。肾上腺切除术使AVP:CRF释放的比例从假手术大鼠的ME中的2:1增加到肾上腺切除组的ME中的8:1。我们认为，AVP:CRF释放的这一比例在体内可能也成立，并且AVP可能是肾上腺切除大鼠中主要的促肾上腺皮质激素刺激物。
