Engleman Eric A, Ingraham Cynthia M, Franklin Kelle M, Keith Carrie M, McClaren Joseph A, Schultz Jonathan A, Morzorati Sandra L, O'Connor Sean, Thielen Richard J, Murphy James M, McBride William J
Department of Psychiatry, Institute of Psychiatric Research, Indiana University School of Medicine, Indianapolis, IN 46220, USA.
Alcohol Clin Exp Res. 2008 Mar;32(3):435-42. doi: 10.1111/j.1530-0277.2007.00587.x. Epub 2008 Jan 22.
The objective of this study was to determine time-course changes in in vivo ethanol (EtOH) concentrations using a novel subcutaneous (s.c.) microdialysis sampling technique. The hypothesis to be tested was that EtOH concentrations in the s.c. fluid would reflect blood EtOH concentrations. If this is the case, then s.c. microdialysis could allow a more detailed analysis of changes in in vivo levels of EtOH under different drinking paradigms.
Adult male and female Wistar rats and male alcohol-preferring (P) rats were used in this study. A loop-style microdialysis probe was designed for s.c. applications. After initial in vitro characterization, probes were implanted under the skin between the shoulder blades. Animals were allowed to recover 4 to 24 hours prior to microdialysis collection (2.0 microl/min flow rate with isotonic saline). In vivo microdialysis experiments were then conducted to determine (i) the extraction fraction (or clearance) using EtOH no-net-flux (NNF) coupled with the alcohol clamp method, (ii) the dose-response and time-course effects after systemic EtOH administration and to compare with blood EtOH levels, and (iii) the time-course changes in EtOH levels during and after an EtOH drinking episode.
In vivo probe recovery (extraction fraction) obtained using the alcohol clamp method was 69 +/- 3%, and was comparable to the in vitro recovery of 73 +/- 2%. For the EtOH dose-response experiment, rats injected i.p. with 0.5, 1.0, or 2.0 g/kg EtOH showed a clear dose-response effect in the s.c. dialysate samples. Peak concentrations (70, 123, and 203 mg%, respectively) were reached by 15 minutes after injection. In an experiment comparing levels of EtOH in s.c. dialysis and arterial blood samples in rats administered 1.0 g/kg EtOH, similar time-course changes in in vivo EtOH concentrations were observed with both i.g. and i.p. EtOH administration. In P rats drinking 15% EtOH during a 1-hour scheduled access period, EtOH levels in s.c. microdialysates rose rapidly over the session and peaked at approximately 50 mg% at 60 to 80 minutes.
Overall, these experiments indicate that s.c. EtOH and blood EtOH concentrations follow a similar time course. Moreover, s.c. microdialysis can be useful as an experimental approach for determining detailed time-course changes in in vivo EtOH concentrations associated with alcohol drinking episodes.
本研究的目的是使用一种新型皮下微透析采样技术来确定体内乙醇（EtOH）浓度的时程变化。要检验的假设是皮下液中的EtOH浓度将反映血液中的EtOH浓度。如果是这样，那么皮下微透析可以对不同饮酒模式下体内EtOH水平的变化进行更详细的分析。
本研究使用成年雄性和雌性Wistar大鼠以及雄性嗜酒（P）大鼠。设计了一种用于皮下应用的环形微透析探针。在初步体外表征后，将探针植入肩胛骨之间的皮下。在进行微透析收集（用等渗盐水以2.0微升/分钟的流速）之前，让动物恢复4至24小时。然后进行体内微透析实验，以确定（i）使用乙醇无净通量（NNF）结合酒精钳夹法的提取分数（或清除率），（ii）全身给予EtOH后的剂量反应和时程效应，并与血液EtOH水平进行比较，以及（iii）EtOH饮用期间和之后EtOH水平的时程变化。
使用酒精钳夹法获得的体内探针回收率（提取分数）为69±3%，与体外回收率73±2%相当。对于EtOH剂量反应实验，腹腔注射0.5、1.0或2.0克/千克EtOH的大鼠在皮下透析液样本中显示出明显的剂量反应效应。注射后15分钟达到峰值浓度（分别为70、123和203毫克%）。在一项比较给予1.0克/千克EtOH的大鼠皮下透析液和动脉血样本中EtOH水平 的实验中，经口和腹腔注射EtOH后，体内EtOH浓度均观察到相似的时程变化。在1小时的预定饮用期内饮用15%EtOH的P大鼠中，皮下微透析液中的EtOH水平在整个时段迅速上升，并在60至80分钟时达到约50毫克%的峰值。
总体而言，这些实验表明皮下EtOH和血液EtOH浓度遵循相似的时程。此外，皮下微透析可作为一种实验方法，用于确定与饮酒事件相关的体内EtOH浓度的详细时程变化。
