Nilsson S, Holmgren S
Eur J Pharmacol. 1976 Sep;39(1):41-51. doi: 10.1016/0014-2999(76)90111-4.
The effects of drugs known from mammalian experiments to interfere with uptake and release of adrenergic transmitters in the sympathetic nerve terminals have been investigated on perfused spleen and isolated spleen strips from the cod. Cocaine and desipramine inhibit the accumulation of 3H-noradrenaline in the perfused spleen, probably by interfering with uptake mechanisms. Both drugs also shift to the left the dose-response curves for noradrenaline and adrenaline on isolated strips, cocaine being most potent. The maximal contraction force of isolated strips also increases after cocaine when noradrenaline is the agonist, but not when methacholine is used or on chronically denervated strips. This effect of cocaine is therefore not due to a general postsynaptic effect. Tyramine and amphetamine both release stored 3H-noradrenaline from the perfused spleen, and tyramine also contracted the spleen strips. In contrast to the situation in mammals, the dose-response curve for tyramine is not affected by cocaine, and tyramine (up to 10(-3) M) present in the bath does not potentiate the dose-response curve for noradrenaline on isolated strips. Different uptake mechanisms for tyramine and noradrenaline into the nerve terminal are therefore suggested for the cod sympathetic fibres. The alpha-adrenoceptor blocking agent phentolamine produces an increase in overflow of label during nerve stimulation at 5Hz in the perfused spleen preloaded with 3H-noradrenaline. An alpha-adrenoceptor-mediated control of the release of catecholamines, similar to that in mammals, appears to be present in the cod.
已知在哺乳动物实验中，某些药物可干扰交感神经末梢肾上腺素能递质的摄取和释放，本研究对鳕鱼的灌注脾脏和离体脾脏条片进行了相关调查。可卡因和地昔帕明抑制灌注脾脏中3H - 去甲肾上腺素的积累，可能是通过干扰摄取机制。这两种药物还使离体条片上去甲肾上腺素和肾上腺素的剂量 - 反应曲线左移，其中可卡因的作用最强。当以去甲肾上腺素为激动剂时，可卡因处理后离体条片的最大收缩力增加，但以乙酰甲胆碱为激动剂时或在长期去神经的条片上则不然。因此，可卡因的这种作用并非由于一般的突触后效应。酪胺和苯丙胺均可使灌注脾脏中储存的3H - 去甲肾上腺素释放，酪胺还可使脾脏条片收缩。与哺乳动物的情况不同，酪胺的剂量 - 反应曲线不受可卡因影响，浴槽中存在的酪胺（高达10(-3) M）也不会增强离体条片上去甲肾上腺素的剂量 - 反应曲线。因此，推测鳕鱼交感神经纤维对酪胺和去甲肾上腺素进入神经末梢存在不同的摄取机制。α - 肾上腺素能受体阻断剂酚妥拉明可使预先加载3H - 去甲肾上腺素的灌注脾脏在5Hz神经刺激期间的标记物溢出增加。鳕鱼似乎存在与哺乳动物类似的α - 肾上腺素能受体介导的儿茶酚胺释放控制机制。
