Heart rate during development in the turtle embryo: effect of temperature
Heart rate during development in the turtle embryo: effect of temperature
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DOI：
10.1007/bf02338288
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
G. Birchard;C. Reiber
中科院分区：
文献类型：
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作者：
G. Birchard;C. Reiber
爬行动物的生长和发育可以在多种身体条件下发生。心血管功能对于这种能力一定是至关重要的。然而，有关发育中的爬行动物心血管功能的信息却很缺乏。先前的研究表明，在爬行动物中，温度对生长和新陈代谢的影响很大程度上局限于早期发育。这项研究探讨了先前观察到的温度影响以及在羊膜脊椎动物中观察到的不同围产期代谢模式是否与心血管功能相关。比较了在 24°C 和 29°C 下孵化的鳄龟蛋 (Chelydra serpentina) 的胚胎和幼体屠体质量、心脏质量和心率 (HR)。 29 °C 下的孵育时间（56.2 天）比 24 °C 下的孵育时间（71:1 天）短。胴体和心脏生长在两种温度下均呈现 S 形模式。然而，随着孵化的进行，心脏生长表现出相对下降。孵化温度显着影响发育过程中的 HR 模式。在 24 °C 下孵化的胚胎的 HR 在孵化的大部分时间内保持恒定（51.8±4.8 min-1）。在孵化前观察到小幅下降，在孵化后立即观察到大幅下降（孵化后，22.3±4.1 min-1）。在发育早期，29°C 下的胚胎 HR 高于 24°C 下的 HR (72.3±3 min-1)。 HR 稳步下降至相当于 24 °C 时的值。 24 °C 和 29 °C 幼体的 HR 没有差异。心输出量（估计为心脏质量和心率的乘积）在早期发育过程中迅速增加，然后在两种温度下急剧减慢。这些数据与温度主要在发育早期发挥作用的建议一致。此外，心血管功能的变化与孵化脊椎动物的代谢变化相关。
Growth and development can occur over a wide range of physical conditions in reptiles. Cardiovascular function must be critical to this ability. However, information on cardiovascular function in developing oping reptiles is lacking. Previous work indicated that in reptiles the effects of temperature on growth and metabolism are largely restricted to early development. This study examined whether the previously observed effects of temperature and different perinatal patterns of metabolism observed in amniotic vertebrates are correlated with cardiovascular function. Embryonic and hatchling carcass mass, heart mass and heart rate (HR) were compared for snapping turtle eggs (Chelydra serpentina) incubated at 24° and 29°C. Incubation time was shorter at 29 °C (56.2 days) than at 24 °C (71:1 days). Carcass and heart growth showed a sigmoidal pattern at both temperatures. However, cardiac growth showed a relative decrease as incubation proceeded. Incubation temperature significantly affected the HR pattern during development. The HR of embryos incubated at 24 °C was constant for most of incubation (51.8±4.8 min-1). A small decrease was observed just prior to and a large decrease immediately following hatching (posthatch, 22.3±4.1 min-1). At 29 °C embryonic HR was greater than at 24 °C early in development (72.3±3 min-1). The HR steadily decreased to values equivalent to those at 24 °C. The HRs of 24 °C and 29 °C hatchlings were not different. Cardiac output (estimated as the product of heart mass and HR) increased rapidly during early development and then slowed dramatically at both temperatures. These data are consistent with the suggestion that temperature exerts its effects primarily early in development. Furthermore, the changes in cardiovascular function are correlated with metabolic changes in hatching vertebrates.