Comprehensive description of the transcriptome of neurointermediate lobe in euhydrated and dehydrated rat

The hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei are important integrative structures that regulate co-ordinated responses to perturbations in cardiovascular homeostasis. Through descending projections from parvocellular neurons to the brainstem, the PVN acts as an autonomic 'premotor nucleus', regulating reflex changes in sympathetic nerve activity that are involved in blood pressure and blood volume regulation. Endocrine responses are mediated through axonal projections from SON and PVN magnocellular neurons (MCNs) to the capillaries of the posterior pituitary neural lobe. In response to dehydration, a massive release of the antidiuretic peptide hormone vasopressin (VP) into the circulation is accompanied by a dramatic functional remodelling of the HNS. We have used microarrays to comprehensively catalogue the genes expressed in the PVN, the SON and the neurointermediate lobe (NIL) of the pituitary gland. Further, we have identified transcripts that are regulated as a consequence of dehydration, as well as RNAs that are enriched in either the PVN or the SON. We suggest that these differentially expressed genes represent candidate regulators and effectors of HNS activity and remodelling. Keywords: DEHYDRATED - NIL In total, 10 Affymetrix Genechip Rat Genome 230 2.0 were used. The experiment compared hypothalamic supraoptic nucleus from 3 day dehydrated and control male Sprague Dawley rats (10-12 weeks). For each chip, tissue from 5 animals was pooled prior to extraction of total RNA and in total 5 chips were used for each condition using independently prepared RNA samples from separate groups of animals.