M.N.L. and Z.L. contributed equally to this work.
Neuronal plasticity and seasonal reproduction in sheep
Article first published online: 12 DEC 2010
© 2010 The Authors. European Journal of Neuroscience © 2010 Federation of European Neuroscience Societies and Blackwell Publishing Ltd
European Journal of Neuroscience
Special Issue: Plasticity of Neuroendocrine Systems
Volume 32, Issue 12, pages 2152–2164, December 2010
How to Cite
Lehman, M. N., Ladha, Z., Coolen, L. M., Hileman, S. M., Connors, J. M. and Goodman, R. L. (2010), Neuronal plasticity and seasonal reproduction in sheep. European Journal of Neuroscience, 32: 2152–2164. doi: 10.1111/j.1460-9568.2010.07530.x
- Issue published online: 12 DEC 2010
- Article first published online: 12 DEC 2010
- Received 22 August 2010, revised 13 October 2010, accepted 19 October 2010
- gonadotropin-releasing hormone;
- thyroid hormone
Seasonal reproduction represents a naturally occurring example of functional plasticity in the adult brain as it reflects changes in neuroendocrine pathways controlling gonadotropin-releasing hormone (GnRH) secretion and, in particular, the responsiveness of GnRH neurons to estradiol negative feedback. Structural plasticity within this neural circuitry may, in part, be responsible for seasonal switches in the negative feedback control of GnRH secretion that underlie annual reproductive transitions. We review evidence for structural changes in the circuitry responsible for seasonal inhibition of GnRH secretion in sheep. These include changes in synaptic inputs onto GnRH neurons, as well as onto dopamine neurons in the A15 cell group, a nucleus that plays a key role in estradiol negative feedback. We also present preliminary data suggesting a role for neurotrophins and neurotrophin receptors as an early mechanistic step in the plasticity that accompanies seasonal reproductive transitions in sheep. Finally, we review recent evidence suggesting that kisspeptin cells of the arcuate nucleus constitute a critical intermediary in the control of seasonal reproduction. Although a majority of the data for a role of neuronal plasticity in seasonal reproduction has come from the sheep model, the players and principles are likely to have relevance for reproduction in a wide variety of vertebrates, including humans, and in both health and disease.