5-羟色胺对人离体胎盘绒毛膜动静脉的影响。

Effects of 5-hydroxytryptamine on human isolated placental chorionic arteries and veins.

作者信息

Reviriego J, Marín J

机构信息

Departamento de Farmacologia y Psiquiatria, Facultad de Medicina, Universidad de Extremadura, Madrid, Spain.

出版信息

Br J Pharmacol. 1989 Apr;96(4):961-9. doi: 10.1111/j.1476-5381.1989.tb11908.x.

DOI:10.1111/j.1476-5381.1989.tb11908.x

PMID:2743086

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1854438/

Abstract

Effects of 5-hydroxytrypamine (5-HT) on cylindrical segments of human chorionic arteries and veins were investigated. Concentrations of 5-HT (up to 3 x 10(-6) M) produced concentration-dependent contractions; higher concentrations induced a reduction of the maximal response. These responses were antagonized by methysergide and ketanserin in a non-competitive manner. The contractions elicited by low 5-HT concentrations were more affected by methysergide (10(-7) M) than by ketanserin (10(-7) M). Ketanserin apparently increased the responses to high 5-HT concentrations in veins. Arteries appeared to be more sensitive to both drugs than veins. Single concentrations of 5-HT elicited transient contractions in both kinds of vessel. 2. Marked tachyphylaxis was seen in segments exposed to high concentrations of 5-HT or in which a concentration-response curve was determined. 3. Contractions induced by 5-HT were reduced in a Ca2+-free medium. Veins were more affected by the Ca2+ antagonists, nifedipine (10(-7) M), nicardipine (10(-5) M) and diltiazem (10(-5) M) than arteries. 4. 5-HT (10(-6) M) enhanced 45Ca2+ uptake in those vessels in which a concentration-response curve had not been previously determined. In veins, this increase was reduced by the three Ca2+ antagonists. 5. The results indicate that 5-HT responses in these vessels were greatly dependent on extracellular Ca2+. A type of 5-HT1-receptor may mediate responses to low 5-HT concentrations, while higher concentrations may activate 5-HT2-receptors. 5-HT may desensitize the latter by interconversion between a high affinity and low affinity state, as suggested by others, a change prevented in part by ketanserin.

摘要

研究了5-羟色胺（5-HT）对人绒毛膜动脉和静脉圆柱状节段的作用。5-HT浓度（高达3×10⁻⁶ M）可产生浓度依赖性收缩；更高浓度则导致最大反应降低。这些反应被麦角新碱和酮色林以非竞争性方式拮抗。低浓度5-HT引起的收缩受麦角新碱（10⁻⁷ M）的影响比受酮色林（10⁻⁷ M）的影响更大。酮色林明显增加了静脉对高浓度5-HT的反应。动脉似乎比静脉对这两种药物更敏感。单一浓度的5-HT在两种血管中均引起短暂收缩。2. 在暴露于高浓度5-HT的节段或测定浓度-反应曲线的节段中观察到明显的快速耐受性。3. 在无钙培养基中，5-HT诱导的收缩减弱。静脉比动脉更易受钙拮抗剂硝苯地平（10⁻⁷ M）、尼卡地平（10⁻⁵ M）和地尔硫䓬（10⁻⁵ M）的影响。4. 5-HT（10⁻⁶ M）增强了那些先前未测定浓度-反应曲线的血管对⁴⁵Ca²⁺的摄取。在静脉中，这种增加被三种钙拮抗剂所降低。5. 结果表明，这些血管中5-HT的反应很大程度上依赖于细胞外钙。一种5-HT1受体可能介导对低浓度5-HT的反应，而更高浓度可能激活5-HT2受体。如其他人所提出的，5-HT可能通过高亲和力和低亲和力状态之间的相互转化使后者脱敏，酮色林可部分阻止这种变化。