Alescio-Lautier B, Soumireu-Mourat B
Laboratoire de Neurobiologie des Comportements, UMR CNRS 6562, Université de Provence, Marseille, France.
Prog Brain Res. 1998;119:501-21. doi: 10.1016/s0079-6123(08)61590-3.
The involvement of arginine8-vasopressin (VP) in learning and memory in the hippocampus is examined in mice using a discriminative learning task. Bilateral dorsal hippocampal lesion blocks the enhancing effect of intracerebroventricular (i.c.v.) injection of VP on retrieval and relearning processes. An additional study showed that immunoneutralization of dorsal hippocampal endogenous VP inhibited the facilitating effect of i.c.v. injection of VP, suggesting that hippocampus is essential for the expression of VP's behavioral effects. Using in situ microinjection, a greater sensitivity of the ventral part of the hippocampus to the memory enhancing effects of VP has been reported. This effect is mediated by vasopressin V1 type receptors and oxytocin receptors. Then, we examined the effects on behavior of VP applied to the ventral hippocampus, in relation to the time of treatment during learning. When the animals have no previous information about the task to learn, a deleterious effect of VP appears (pre-first session treatment). Regarding memory consolidation, the effects of VP may depend upon the previous level of performance acquired by the animals since, when injected after the first learning session, the peptide slightly delayed performance, whereas when the injection took place after the second learning session, it enhanced learning. Concerning memory retrieval, the effects of VP depend on the quality of the previously stored information. The fact that VP did not generate the same behavioral effects when the treatment was performed at the beginning or in the middle of the learning processes, suggests that mnemonic context is an important factor in understanding the effect of VP on memory in the ventral hippocampus. Finally, the role of hippocampal adrenergic receptors in the enhancing VP effects on memory retrieval has been examined. The facilitatory effects of VP seem to depend upon the functional state of both alpha- and beta-adrenergic receptors, but further studies will be necessary to clarify the role played by each receptor type in retrieval processes, and to determine the relationships that might exist between them.
利用辨别性学习任务，在小鼠中研究了精氨酸8 - 血管加压素（VP）在海马体学习和记忆中的作用。双侧背侧海马体损伤会阻断脑室内（i.c.v.）注射VP对检索和再学习过程的增强作用。另一项研究表明，背侧海马体内源性VP的免疫中和作用会抑制i.c.v.注射VP的促进作用，这表明海马体对于VP行为效应的表达至关重要。通过原位微注射，已有报道称海马体腹侧部分对VP的记忆增强作用更为敏感。这种效应是由血管加压素V1型受体和催产素受体介导的。然后，我们研究了在学习过程中不同时间点将VP应用于腹侧海马体对行为的影响。当动物对要学习的任务没有先前信息时，VP会产生有害作用（首次训练前治疗）。关于记忆巩固，VP的作用可能取决于动物先前获得的表现水平，因为在第一次学习训练后注射该肽会轻微延迟表现，而在第二次学习训练后注射则会增强学习效果。关于记忆检索，VP的作用取决于先前存储信息的质量。当在学习过程开始或中间进行治疗时，VP产生不同行为效应这一事实表明，记忆背景是理解VP对腹侧海马体记忆影响的一个重要因素。最后，研究了海马体肾上腺素能受体在增强VP对记忆检索作用中的作用。VP的促进作用似乎取决于α - 和β - 肾上腺素能受体的功能状态，但需要进一步研究来阐明每种受体类型在检索过程中所起的作用，并确定它们之间可能存在的关系。
