Satake N, Morton B E
Pharmacol Biochem Behav. 1979 Apr;10(4):449-56. doi: 10.1016/0091-3057(79)90216-8.
We had shown that synthetic rat scotophobin A caused several effects upon goldfish, apparently mediated by the pineal gland. Here we report that norepinephrine decreased goldfish dark avoidance in a manner that was blocked by scotophobin or pinealectomy. Increased dark avoidance was caused by either propranolol or scotophobin alone. Certain components of the pineal melatonin pathway also affected goldfish light-dark preference: serotonin, and especially N-acetylserotonin, increased dark avoidance, as did the hydroxyindole-O-methyl-transferase (HIOMT) product inhibitor, S-adenosyl-homocysteine. Melatonin and S-adenosyl-methionine were without effect in this regard. Pinealectomy prevented the dark avoidance increase caused by serotonin and N-acetylserotonin. These data suggested that increased dark avoidance behavior in goldfish was correlated with N-acetylserotonin buildup in the pineal, and that scotophobin could cause this, if it were to inhibit pineal HIOMT. To test this hypothesis the effect of various agents upon pineal melatonin levels was determined. Scotophobin was found to both reduce pineal melatonin and to block the melatonin-increasing effect of N-acetylserotonin. This led to the discovery that, indeed, scotophobin was an effective inhibitor (KI50, 6 x 10(-7) M) of purified bovine HIOMT.
我们已经表明，合成的大鼠避光蛋白A对金鱼产生了多种影响，显然是由松果体介导的。在此我们报告，去甲肾上腺素以一种被避光蛋白或松果体切除所阻断的方式降低了金鱼的暗回避行为。单独使用普萘洛尔或避光蛋白都会导致暗回避增加。松果体褪黑素途径的某些成分也会影响金鱼的明暗偏好：血清素，尤其是N-乙酰血清素，会增加暗回避，羟基吲哚-O-甲基转移酶（HIOMT）产物抑制剂S-腺苷同型半胱氨酸也会如此。褪黑素和S-腺苷甲硫氨酸在这方面没有作用。松果体切除可防止血清素和N-乙酰血清素引起的暗回避增加。这些数据表明，金鱼暗回避行为的增加与松果体中N-乙酰血清素的积累相关，并且如果避光蛋白抑制松果体HIOMT，它可能会导致这种情况。为了验证这一假设，我们测定了各种试剂对松果体褪黑素水平的影响。发现避光蛋白既能降低松果体褪黑素水平，又能阻断N-乙酰血清素增加褪黑素的作用。这导致发现，事实上，避光蛋白是纯化牛HIOMT的有效抑制剂（抑制常数50，6×10⁻⁷ M）。
