Eglen R M, Whiting R L
Institute of Pharmacology, Syntex Research, Palo Alto, California 94304.
J Cardiovasc Pharmacol. 1989 Jan;13(1):45-51.
The positive chronotropic response to 5-hydroxytryptamine (5-HT) in the isolated guinea pig atria was analyzed. The response to 5-HT was compared with the effects of 5-carboxamidotryptamine (5-CT), 8-dihydroxydiphenylaminotetralin (8-OH-DPAT), isoprenaline, prenalterol, dobutamine, salbutamol, and norepinephrine (NE). In comparison to isoprenaline 5-HT, prenalterol, dobutamine, salbutamol, and NE acted as partial agonists, whereas 5-CT and 8-OH-DPAT did not produce a response. The response to 5-HT was unaffected by 1 microM methysergide, metergoline, ketanserin, MDL 72222, ICS 205-930, phentolamine, or 0.1 mM hexamethonium. However, the beta-adrenoceptor antagonists, pindolol and atenolol, antagonized the response to 5-HT in a noncompetitive manner. The response to 5-HT was unaffected by reserpinization or beta-adrenoceptor desensitization. Thus, the positive chronotropic response to 5-HT in this preparation is a direct effect but is not mediated by 5-HT1-like, 5-HT2, or 5-HT3 receptors.
分析了5-羟色胺（5-HT）对离体豚鼠心房的正性变时反应。将对5-HT的反应与5-羧酰胺色胺（5-CT）、8-二羟基二苯氨基四氢萘（8-OH-DPAT）、异丙肾上腺素、普瑞特罗、多巴酚丁胺、沙丁胺醇和去甲肾上腺素（NE）的作用进行了比较。与异丙肾上腺素相比，5-HT、普瑞特罗、多巴酚丁胺、沙丁胺醇和NE起部分激动剂的作用，而5-CT和8-OH-DPAT未产生反应。对5-HT的反应不受1 microM麦角新碱、美替拉酮、酮色林、MDL 72222、ICS 205-930、酚妥拉明或0.1 mM六甲铵的影响。然而，β-肾上腺素能受体拮抗剂吲哚洛尔和阿替洛尔以非竞争性方式拮抗对5-HT的反应。对5-HT的反应不受利血平化或β-肾上腺素能受体脱敏的影响。因此，该制剂中对5-HT的正性变时反应是一种直接效应，但不是由5-HT1样、5-HT2或5-HT3受体介导的。
