禁食离体灌流鼠心对去甲肾上腺素和异丙肾上腺素的反应

Response of Isolated Perfused Hearts From Fasted Rats to Norepinephrine and Isoprenaline

目的：研究禁食２４ｈ的离体鼠心对去甲肾上腺素（ＮＥ）和异丙肾上腺素（ＩＳＯ）的反应。方法：用每４ｍｉｎ含不同浓度的ＮＥ或ＩＳＯ的Ｋ－Ｈ液灌流进食和禁食离体鼠心。连续记录了左心室发展压（ＬＶＤＰ）和心率（ＨＲ）。结果：对ＩＳＯ和ＮＥ反应的量效曲线均右移。对ＩＳＯ反应的禁食鼠的ＥＣ５０高于进食鼠（禁食鼠１．００Ｅ－７．７１２±０．０４２６，进食鼠１．００Ｅ－８．２８±０．０５１５ｎ＝４，Ｐ＜０．００１）；对ＮＥ反应的心律失常发生率明显低于进食鼠（禁食鼠４６．８０±６．３４次／３２分，进食鼠８３．８０±１０．１８次／３２分，ｎ＝５，Ｐ＜０．０１）。对ＩＳＯ反应两组心律失常发生率无明显差异。结论：禁食鼠心对ＮＥ和ＩＳＯ的反应均受抑制。这对心肌有保护作用。

Objective: This paper was to investigate the response of isolated fasted (for 24 h) rat hearts to Norepinephrine (NE) and isoprenaline (ISO). Methods: We perfused isolated hearts from fed and fasted rats per 4 minutes with Krebs Henseleit buffer containing different concentrations of NE or ISO. The left ventricular developed pressure (LVDP) and heart rate (HR) were continuously recorded. Results: The dose effect curve of response to ISO or to NE moved right. The effective concentration 50% (EC 50 ) to ISO in fasted rat hearts (1.00E-7.712±0.0426) was higher than that in fed rat hearts (1.00E-8.28±0.0515) ( n =4 P <0.001). No statistically significant difference was present for EC 50 to NE in both groups. The incidence of NE induced arrhgthmia was lower in fasted rat hearts (46.80±6.34 beat/32 min) than that in fed rat (83.80±10.18) ( n =5 P <0.01). The incidence of ISO induced arrhythmia was no significant difference in both groups. Conclusion: Response to NE and ISO in isolated fasted rat hearts was suppressed. Fasting exerted protective effect on myocardium.