FETAL SWALLOWING--ONTOGENY AND REGULATION

口渴和吞咽是人类的基本生物系统， 调节体内水分平衡。 子宫内吞咽，由 胎儿"口渴"和皮质电状态，导致 羊水水分、电解质和内分泌因子。 期间 围产期，激素和生理因素调节的印记 口渴可能会永久性地改变成年人的体液平衡。 因此研究 胎儿"口渴"和吞咽有助于理解 液体调节机制的发展。 此外，分析 食管液流模式和胎儿行为状态可以提供 了解新生儿口渴，反流和改变 呼吸模式 自发和口渴介导的吞咽行为 在绵羊和人类子宫内发育成熟。 因此， 有必要研究个体发育的口渴调节。 我们有 开发了一种慢性绵羊胎儿模型，用于吞咽的量化 活动和体积，并同时测定胎儿行为 状态 我们已经证明，类似于成人，胎儿吞咽 两者都是自发发生的，并且可以被致渴因子刺激。 然而，胎儿对已知致渴刺激的反应可能与已知致渴刺激不同。 成年人了此外，自发性胎儿吞咽活动可能受到抑制 与行为状态的改变相一致 该项目将 表征自发性胎儿吞咽的个体发育， 昼夜节律和与胎儿行为状态成熟的关系。 原发性全身刺激对胎儿吞咽刺激的个体发育 （高渗和血管紧张素II; AII）和精氨酸的调节 血管加压素（AVP）和心钠素（ANF）将被研究。 的 AII和AVP刺激的吞咽的受体介导将用 选择性受体拮抗剂。 此外，中枢刺激和 通过主要内分泌因子（AII、AVP、ANF）抑制吞咽将 被探索。 绵羊模型提供了研究的机会， 早熟物种，个体发育的"口渴"生理，一个重要的，但 围产期生理学相对未被探索的领域。

Thirst and swallowing represent a fundamental biologic system for the regulation of body water homeostasis. In-utero swallowing, modulated by fetal "thirst" and electrocortical state, results in the resorption of amniotic fluid water, electrolytes and endocrine factors. During the perinatal period, imprinting of hormonal and physiologic factors regulating thirst may permanently alter adult fluid balance. Therefore, the study of fetal "thirst" and swallowing can contribute to an understanding of the development of mechanisms for fluid regulation. In addition, analysis of patterns of esophageal fluid flow and fetal behavioral states may provide insight into the association of neonatal thirst, regurgitation and altered breathing patterns. Spontaneous and thirst-mediated swallowing behavior develop and mature in-utero in sheep and humans. Thus, a fetal model is necessary to investigate the ontogenesis of thirst regulation. We have developed a chronic ovine fetal model for the quantification of swallowing activity and volume and the simultaneous determination of fetal behavioral state. We have demonstrated that, similar to the adult, fetal swallowing both occurs spontaneously and can be stimulated by dipsogenic factors. However, fetal responses to known dipsogenic stimuli may differ from the adult. Furthermore, spontaneous fetal swallowing activity may be suppressed in accordance with behavioral state alterations. This project will characterize the ontogeny of spontaneous fetal swallowing, the presence of diurnal rhythms and the association with fetal behavioral state maturation. The ontogeny of fetal swallowing stimulation by primary systemic stimuli (hyperosmolality and angiotensin II; AII) and the modulation by arginine vasopressin (AVP) and atrial natriuretic factor (ANF) will be studied. The receptor mediation of AII and AVP stimulated swallowing will be probed with selective receptor antagonists. In addition, the central stimulation and suppression of swallowing by primary endocrine factors (AII, AVP, ANF) will be explored. The ovine model offers the opportunity to study, in a precocial species, the ontogeny of "thirst" physiology, an important but relatively unexplored area of perinatal physiology.