Quertemont E, De Witte P
Biologie du Comportement, Université Catholique de Louvain, Place Croix du Sud 1, 1348, Louvain-La-Neuve, Belgium.
Pharmacol Biochem Behav. 2001 Mar;68(3):449-54. doi: 10.1016/s0091-3057(00)00486-x.
Acetaldehyde, the first ethanol metabolite, has been suggested to mediate some of the behavioral effects of ethanol and particularly its reinforcing properties, although this later hypothesis remains extremely controversial. While several studies demonstrated the reinforcing effects of brain acetaldehyde, blood acetaldehyde accumulation is believed to be primarily aversive. In the present study, a conditioned reinforcement procedure has been used to investigate the reinforcing and/or aversive effects of intraperitoneal injections of both acetaldehyde and ethanol in Wistar rats. An olfactory stimulus was paired with daily injections of either ethanol (0, 0.25, 0.5, 1 and 2 g/kg) or acetaldehyde (0, 10, 20, 100 and 150 mg/kg). After eight conditioning sessions, all rats were tested for their stimulus preference or aversion. The results show that conditioning with small, 0.25 and 0.5 g/kg, ethanol doses induced neither preference nor aversion for the olfactory cue. In contrast, higher ethanol doses (1.0 and 2.0 g/kg) resulted in significant stimulus aversions. Acetaldehyde conditioning led to a biphasic stimulus preference, with a maximal preference around 20 mg/kg acetaldehyde. No evidence of aversive effects was found with increasing doses of acetaldehyde, even with concentrations close to the lethal limit. The present study clearly shows that systemic acetaldehyde injections induced significant stimulus preferences. This suggests that acetaldehyde may be, at least in part, responsible for the reinforcing effects of alcohol intake.
乙醛是乙醇的首个代谢产物，有人认为它介导了乙醇的一些行为效应，尤其是其强化特性，尽管后一种假说仍极具争议。虽然多项研究证明了脑内乙醛的强化作用，但血液中乙醛的积累被认为主要是令人厌恶的。在本研究中，采用条件强化程序来研究腹腔注射乙醛和乙醇对Wistar大鼠的强化和/或厌恶效应。将一种嗅觉刺激与每日注射乙醇（0、0.25、0.5、1和2克/千克）或乙醛（0、10、20、100和150毫克/千克）配对。经过八次条件训练后，对所有大鼠进行刺激偏好或厌恶测试。结果表明，用低剂量（0.25和0.5克/千克）乙醇进行条件训练既未引起对嗅觉线索的偏好也未引起厌恶。相反，较高剂量的乙醇（1.0和2.0克/千克）导致明显的刺激厌恶。乙醛条件训练导致双相刺激偏好，在约20毫克/千克乙醛时偏好最大。即使使用接近致死极限的浓度，随着乙醛剂量增加也未发现厌恶效应的证据。本研究清楚地表明，全身注射乙醛会引起明显的刺激偏好。这表明乙醛可能至少部分地导致了酒精摄入的强化效应。
