Microarray analysis of the dynamics of gene expression plasticity in the supraoptic nucleus following dehydration

The hypothalamo-neurohypophyseal system (HNS) is crucial for osmoregulation. The HNS consists of the magnocellular neurons (MCNs) of the hypothalamus that have their axons terminating in the posterior pituitary. The HNS exerts its role in water balance via the release of the anti-diuretic hormone vasopressin (VP). Following dehydration VP is released into the general circulation. By binding to V2-type receptors located in the kidney, VP decrease the amount of water lost in urine. An osmotic stimulus also elicits an increase in VP gene expression and a functional remodelling of the entire HNS. We want to understand this plasticity in terms of the co-ordinated reprogramming of gene expression. We thus used Affymetrix U34a rat GeneChips to examine the dynamics of gene expression plasticity over the duration of a dehydration stimulus. Arrays were probed in triplicate with targets derived from SON of control rats, and rats dehydrated for 1 and for 3 days. Transcripts were thus identified that respond early to dehydration (up- or down-regulated after only 1day of dehydration), or that respond late (up- or down-regulated at 3 days of dehydration). Keywords: SON, Dehydration, clone 3 chips hybridised with control SON were compared to 3 chips hybridised with 1 day dehydrated SON and 3 chips hybridised with 3 day dehydrated SON