SEROTONIN RECEPTORS: CHARACTERIZATION & ONTOGENY

5-羟色胺（5-HT）是肠道中的神经递质， 神经系统（ENS）。 两种肠神经5-HT受体 已被鉴定为5-HT 1 P和5-HT 3。 5-HT 1 P受体 5-HT 1 P受体的拮抗剂包括N- 乙酰基-5-羟丙基-5-羟色氨酸酰胺（5-HTP-DP）和 24924巴西雷亚尔。 在发育过程中，5-HT 1 P受体在发育后出现。 能神经元的出现。 5-HT 3受体不是 用3 H-5-HT标记; 5-HT 3受体的拮抗剂包括ICS 205- 930、BRL 43694（格拉司琼）和GR 65630。 无论是 分布在肠壁，也不是5-HT 3的个体发育 受体以前已经研究过。 现建议 用放射性配体研究小鼠肠道中的肠道5-HT 3受体 结合技术，使用快速过滤和肠溶 膜和放射自显影与3 H-格拉司琼和3 H-GR 65630。 特异性结合将被定义为ICS 205-930取代的结合。 5-HT 3受体的位置将在成人中确定， 胎儿肠道和它们在个体发育中出现的时间将是 与5-HT 1 P受体相关。 选择性破坏 用5，7-二羟色胺（5，7-DHT）处理的多巴胺能神经突将 用于探索它们对发育，成熟， 和5-HT 1 P受体的维持。 5-HT本身的能力 影响5-HT 1 P受体发育的机制将单独探讨。 通过检测5-HT 1 P受体，研究5-HT的作用 在特定拮抗剂存在下的发育和成熟 在通过抑制色氨酸消耗5-HT后， 羟化酶 实验将用胎儿肠道的外植体进行 在器官型组织培养中生长并在体内发育 后肠，其中5-HT 1 P受体在前3周内发育 生命 6-羟多巴胺化学交感神经切除术 诱导5-HT 1 P受体的快速上调。 的影响 6-现在将确定5-HT 3受体上的OHDA。 此外，本发明还提供了一种方法， 将进行研究以确定6-OHDA对 肠神经5-HT受体是由于去甲肾上腺素的损失 (NE)，并具体涉及销毁 肾上腺素能神经元的去甲肾上腺素能神经支配。 这些 实验将利用酪氨酸羟化酶抑制来消耗 BE与细胞色素定量细胞化学显示 氧化酶活性，以评估交感神经切除术对强直性脊柱炎的影响 肾上腺素能神经元的活动。 最后，由于两种维生素E 神经元和5-HT 1 P受体已经存在，而肠道 含有神经元的增殖前体， 血管活性肠肽（VIP）与降钙素基因相关 肽（CGRP）免疫反应性的可能性存在， 肾上腺素能神经元可能会影响 这些晚期发育的神经元。 这一可能性将由 测定5，7-DHT或5-HT 1 P慢性抑制的作用 和/或5-HT 3受体的生日和最终数量的 VIP和CGRP免疫反应神经元。 这些影响 对早期发育的神经肽Y免疫反应性 神经元也将作为对照进行检查。 最后，如果影响 研究将确定是否受影响， 神经元实际上接受了多巴胺能突触 这些实验 将提高对先天性心脏病发病机制的认识， 肠神经肌肉发育缺陷，将是重要的 在评估精神药物的安全性时， 妊娠期5-羟色胺受体的肾上腺素能神经元

5-hydroxytryptamine (5-HT) is a neurotransmitter in the enteric nervous system (ENS). Two types of enteric neural 5-HT receptor have been identified, 5-HT1P and 5-HT3. The 5-HT1P receptor is labeled by 3H-5-HT; antagonists at 5-HT1P receptors include N- acetyl-5-hydroxytryptophyl-5-hydroxytryptophan amide (5-HTP-DP) and BRL 24924. During developments 5-HT1P receptors arise after the appearance of serotonergic neurons. 5-HT3 receptors are not labeled by 3H-5-HT; antagonists at 5-HT3 receptors include ICS 205- 930, BRL 43694 (granisetron) and GR 65630. Neither the distribution in the wall of the bowel, nor the ontogeny of 5-HT3 receptors have previously been studied. It is now proposed to study enteric 5-HT3 receptors in the murine gut by radioligand binding techniques, using both rapid filtration of enteric membranes and radioautography with 3H-granisetron and 3H-GR 65630. Specific binding will be defined as that displaced by ICS 205-930. The location of 5-HT3 receptors will be determined in the adult and fetal bowel and the timing of their appearance in ontogeny will be related to that of 5-HT1P receptors. Selective destruction of serotonergic neurites with 5,7-dihydroxytryptamine (5,7-DHT) will be used to explore their influence on the development, maturation, and maintenance of 5-HT1P receptors. The ability of 5-HT itself to affect 5-HT1P receptor development will be separately explored. The role of 5-HT will be studied by examining 5-HT1P receptor development and maturation in the presence of specific antagonists and after depletion of 5-HT by inhibition of tryptophan hydroxylase. Experiments will be done with explants of fetal gut grown in organotypic tissue culture and in vivo with developing hindgut, in which 5-HT1P receptors develop during the first 3 weeks of life. Chemical sympathectomy with 6-hydroxydopamine (6-OHDA) induces a rapid upregulation of 5-HT1P receptors. The effect of 6-OHDA on 5-HT3 receptors will now be ascertained. In addition, studies will be done to determine whether the effect of 6-OHDA on enteric neural 5-HT receptors is due to loss of norepinephrine (NE), and is specifically related to destruction of the noradrenergic innervation of serotonergic neurons. These experiments will utilize tyrosine hydroxylase inhibition to deplete BE and the quantitative cytochemical demonstration of cytochrome oxidase activity to evaluate effect of sympathectomy on the tonic activity of serotonergic neurons. Finally, since both serotonergic neurons and 5-HT1P receptors are already present while the gut contains the proliferating precursors of neurons that contain vasoactive intestinal polypeptide (VIP) and calcitonin gene related peptide (CGRP) immunoreactivity the possibility exists that serotonergic neurons may influence the phenotypic expression of these late-developing neurons. This possibility will be tested by determining the effects of 5,7-DHT or chronic inhibition of 5-HT1P and/or 5-HT3 receptors on the birthdays and ultimate numbers of VIP- and CGRP-immunoreactive neurons. The effect of these treatments on the earlier-developing neuropeptide Y-immunoreactive neurons will also be examined as a control. Finally, if effects ar found, studies will be done to determine whether affected neurons actually receive serotonergic synapses. These experiments will enhance understanding of the pathogenesis of congenital defects of enteric neuromuscular development and will be important in evaluating the safety of psychoactive drugs that affect serotonergic neurons of 5-HT receptors in pregnancy.