Galzin A M, Langer S Z
Naunyn Schmiedebergs Arch Pharmacol. 1986 Jul;333(3):330-3. doi: 10.1007/BF00512949.
The 5-hydroxytryptamine (5HT) receptor agonist, 5-methoxytryptamine, inhibited in a concentration-dependent manner the electrically-evoked release of 3H-5HT from superfused rat hypothalamic slices, with an IC50 of 560 nmol/l, without affecting the spontaneous outflow of radioactivity. In the presence of the selective monoamine oxidase B (MAO B) inhibitor, (-)-deprenyl (1 mumol/l), the concentration-effect curve for 5-methoxytryptamine was shifted significantly to the left, and the IC50 was decreased to 25 nmol/l. Under the same experimental conditions, the potency of the 5HT receptor agonist lysergic acid diethylamide (LSD) at inhibiting the electrically-evoked release of 3H-5HT was the same in the presence as well as in the absence of (-)-deprenyl. The IC50 values for LSD were 34 nmol/l in the absence of deprenyl, and 31 nmol/l in the presence of the MAO B inhibitor. It is concluded that deprenyl potentiates the inhibition by 5-methoxytryptamine of 3H-5HT release, by preventing its inactivation through MAO B. Since 5-methoxytryptamine may be present in the pineal gland of some species, the potent effects of this 5-HT receptor agonist on serotoninergic neurotransmission may be of physiological relevance.
5-羟色胺（5HT）受体激动剂5-甲氧基色胺以浓度依赖的方式抑制了从灌流大鼠下丘脑切片中电诱发的3H-5HT释放，IC50为560 nmol/l，且不影响放射性的自发流出。在选择性单胺氧化酶B（MAO B）抑制剂（-）-司来吉兰（1 μmol/l）存在的情况下，5-甲氧基色胺的浓度-效应曲线显著左移，IC50降至25 nmol/l。在相同实验条件下，5HT受体激动剂麦角酸二乙胺（LSD）抑制电诱发的3H-5HT释放的效力在有和没有（-）-司来吉兰时相同。在没有司来吉兰时，LSD的IC50值为34 nmol/l，在MAO B抑制剂存在时为31 nmol/l。得出的结论是，司来吉兰通过防止5-甲氧基色胺经MAO B失活，增强了其对3H-5HT释放的抑制作用。由于5-甲氧基色胺可能存在于某些物种的松果体中，这种5HT受体激动剂对5-羟色胺能神经传递的强效作用可能具有生理相关性。
