Park K H, Long J P, Cannon J G
Department of Pharmacology, College of Medicine and Pharmacy, University of Iowa City 52242.
Can J Physiol Pharmacol. 1991 Dec;69(12):1855-60. doi: 10.1139/y91-274.
Serotonin1A receptor agonists, 8-hydroxy-2-(di-n-propylamino)tetralin and 10-methyl-11-hydroxyaporphine, inhibited electrical stimulation-induced contraction of the guinea-pig ileum. These agonists also inhibited the pressor and tachycardiac responses to low frequency (0.25 Hz) but not to high frequency (2.0 Hz) electrical stimulation of the sympathetic nervous system in pithed rats. Serotonin1B receptor agonist RU 24969 inhibited pressor and tachycardiac responses to both low and high frequencies of stimulation in pithed rats. In the cat nictitating membrane, serotonin1A receptor agonists did not alter contractions elicited by electrical stimulation (0.1-3.0 Hz). Serotonin not only contracted the cat nictitating membrane but also facilitated contractile responses to low frequency (0.1-1.0 Hz) stimulation. The contractile effect of serotonin in the cat nictitating membrane was blunted by bretylium, methysergide, and ketanserin, but not by metoclopramide. The facilitatory effect of serotonin was antagonized by methysergide, but not by ketanserin, pindolol, propranolol, or metoclopramide. These results suggest that serotonin1A receptors modulate autonomic neurotransmission in the guinea-pig ileum and pithed rats, but not in the cat nictitating membrane. Serotonin contracts the cat nictitating mebrane via serotonin2 subtypes, while facilitating stimulated contractile responses through the serotonin1-like receptors.
血清素1A受体激动剂8-羟基-2-（二正丙基氨基）四氢萘和10-甲基-11-羟基阿朴啡抑制豚鼠回肠的电刺激诱导收缩。这些激动剂还抑制了去大脑大鼠对低频（0.25Hz）但不抑制对高频（2.0Hz）交感神经系统电刺激的升压和心动过速反应。血清素1B受体激动剂RU 24969抑制去大脑大鼠对低频和高频刺激的升压和心动过速反应。在猫的瞬膜中，血清素1A受体激动剂不改变电刺激（0.1 - 3.0Hz）引起的收缩。血清素不仅使猫的瞬膜收缩，还促进对低频（0.1 - 1.0Hz）刺激的收缩反应。血清素在猫瞬膜中的收缩作用被溴苄铵、麦角新碱和酮色林减弱，但不受甲氧氯普胺影响。血清素的促进作用被麦角新碱拮抗，但不受酮色林、吲哚洛尔、普萘洛尔或甲氧氯普胺影响。这些结果表明，血清素1A受体调节豚鼠回肠和去大脑大鼠的自主神经传递，但不调节猫瞬膜的自主神经传递。血清素通过血清素2亚型使猫瞬膜收缩，同时通过血清素1样受体促进刺激的收缩反应。
