Boosting Maternal Memory

Science's STKE  08 Apr 2003:
Vol. 2003, Issue 177, pp. tw133-TW133
DOI: 10.1126/stke.2003.177.tw133

Tomizawa et al. discovered that oxytocin, a hormone that is crucial to both labor and lactation and also stimulates maternal behaviors, may mediate a motherhood-dependent improvement in spatial memory and may promote long-lasting changes in synaptic transmission in the hippocampus, a region implicated in the acquisition of spatial memory. Anyone who has lived with an infant can appreciate the changes in life-style and behavior that raising a newborn demands. In rats, giving birth and nursing pups improves spatial memory, a change that may enable the mother to forage successfully for her new family. Tomizawa et al. showed that intracerebroventricular administration of oxytocin improved long-term spatial memory in nulliparous female mice, whereas administration of an oxytocin antagonist during pregnancy and after birth inhibited memory improvement in multiparous mice. In hippocampal slices from nulliparous mice, oxytocin promoted the development of a long-lasting phase of long-term potentiation (L-LTP) without affecting basal synaptic transmission, short-term plasticity, or the initial phase of long-term potentiation. Mitogen-activated protein kinase (MAPK) inhibitors antagonized oxytocin-dependent facilitation of L-LTP and inhibited an oxytocin-dependent increase in phosphorylation of the cyclic adenosine monophosphate response element-binding protein (CREB). Hippocampal slices from multiparous mice displayed L-LTP and CREB phosphorylation similar to those observed in oxytocin-treated slices from nulliparous mice; both facilitation of L-LTP and enhanced levels of CREB phosphorylation were inhibited by intraventricular administration of the oxytocin antagonist. Monks et al. discuss some of the implications of this research in an entertaining News and Views article.

K. Tomizawa, N. Iga, Y.-F. Lu, A. Moriwaki, M. Matsushita, S.-T. Li, O. Miyamoto, T. Itano, H. Matsui, Oxytocin improves long-lasting spatial memory during motherhood through MAP kinase cascade. Nature Neurosci. 6, 384-390 (2003). [Online Journal]

D. A. Monks, J. S. Lonstein, S. M. Breedlove, Got milk? Oxytocin triggers hippocampal plasticity. Nature Neurosci. 6, 327-328 (2003). [Online Journal]