Physiological doses of 17-β Estradiol (E2) rapidly induce mitogen-activated protein kinase (MAPK) phosphorylation in a variety of cell culture and tissue explant preparations. Rapid MAPK phosphorylation has been implicated as a critical step in estrogen's effects on neuronal activity, gene transcription and neuroprotection. The present series of in vivo experiments were designed to determine whether acute administration of estrogen rapidly increased extracellular signal-regulated protein kinase (ERK) 2 phosphorylation. Brains were harvested 20 min after a single i.p. injection of 15 μg/kg of 17-β or 17-α estradiol. Twelve brain structures were micro-dissected, homogenized and processed for Western blotting. E2-treated rats exhibited a statistically significant increase in ERK2 phosphorylation in the diagonal band of Broca, rostral nucleus accumbens, paraventricular nucleus, arcuate nucleus and anteromedial visual cortex. Administration of the same dose of 17-α estradiol did not enhance ERK phosphorylation in any of the brain regions examined. The in vivo data presented here extend previously published in vitro data indicating that E2 rapidly activates MAPK in primary neuronal cultures, explants and cell lines. These data also indicate that MAPK activation is a potential mediator of estrogens effects in some but not all estrogen receptor containing regions of the brain.
|Original language||English (US)|
|Number of pages||10|
|State||Published - 2005|
Bibliographical noteFunding Information:
We would like to acknowledge the assistance of Dr. David Hess for assaying circulating estrogen levels, Dr. Gary Sexton for helpful comments with statistics, and Drs. Robert Shapiro and Lisa Marriott for critically reviewing the manuscript and helpful discussions. Portions of the data have been presented at the Society for Neuroscience’s 34th annual meeting. This work was supported by NS43330 (O.K.R), NS203311 and AG05136-18 (D.M.D.) and an Oregon Alzheimer’s Disease Center pilot grant (NIH P3008017) (D.N.B.).
- Arcuate nucleus
- Diagonal band of Broca
- Nucleus accumbens
- Rapid signaling
- in vivo