在常氧和缺氧条件下，L-5-羟色氨酸对胎羊呼吸运动的刺激作用。

Stimulation of breathing movements by L-5-hydroxytryptophan in fetal sheep during normoxia and hypoxia.

Fletcher D J, Hanson M A, Moore P J, Nijhuis J G, Parkes M J

Department of Physiology and Biochemistry, University of Reading, Whiteknights.

J Physiol. 1988 Oct;404:575-89. doi: 10.1113/jphysiol.1988.sp017307.

Abstract

In fetal lambs in late gestation, systemic infusion of L-5-hydroxytryptophan (L-5-HTP) during normoxia greatly increases the incidence of fetal breathing movements (FBM) and high-voltage electrocortical activity (HV ECoG). It also induces FBM during HV ECoG and increases blood pressure. To investigate its mechanism of action, L-5-HTP was administered in conjunction with the 5-hydroxy-tryptamine (5-HT) antagonists ketanserin or cyproheptadine. L-5-HTP was also infused with or without the antagonists during hypoxia, to test whether it would overcome the inhibition of FBM by hypoxia. 2. When L-5-HTP was given in normoxia, cyproheptadine blocked and ketanserin reduced the increase in blood pressure, both drugs blocked the stimulation of FBM, but neither drug prevented the induction of prolonged episodes of HV ECoG. 3. In hypoxia, L-5-HTP similarly stimulated FBM. This effect was also blocked by cyproheptadine and was delayed by ketanserin. 4. The antagonism of the effects of L-5-HTP on blood pressure and the incidence of FBM in normoxia and hypoxia is consistent with the action of L-5-HTP via 5-HT receptors. At present there is no clear explanation of the mechanism by which L-5-HTP induces HV ECoG.

摘要

在妊娠晚期的胎羊中，常氧条件下全身输注L-5-羟色氨酸（L-5-HTP）可显著增加胎儿呼吸运动（FBM）和高电压皮质电活动（HV ECoG）的发生率。它还会在HV ECoG期间诱发FBM并升高血压。为研究其作用机制，将L-5-HTP与5-羟色胺（5-HT）拮抗剂酮色林或赛庚啶联合使用。在缺氧期间，也在有或没有拮抗剂的情况下输注L-5-HTP，以测试它是否能克服缺氧对FBM的抑制作用。2. 在常氧条件下给予L-5-HTP时，赛庚啶可阻断且酮色林可降低血压升高，两种药物均阻断对FBM的刺激，但两种药物均不能阻止长时间HV ECoG发作的诱发。3. 在缺氧条件下，L-5-HTP同样刺激FBM。这种作用也被赛庚啶阻断，且被酮色林延迟。4. L-5-HTP在常氧和缺氧条件下对血压和FBM发生率的作用拮抗与L-5-HTP通过5-HT受体发挥作用一致。目前对于L-5-HTP诱发HV ECoG的机制尚无明确解释。