Differences in POMC and TRPV 3 expression in the brainstem of Obese Prone and Obese resistant rats

Abstract

The aim of this study is to examine and establish the differences in pro‐opiomelanocortin (POMC) and Transient Receptor Potential Vannilloid 3 (TRPV3) expression in the brainstem between Obese Prone (OP) and Obese Resistant (OR) rats. OP and OR rats were fed for seven days on a high fat diet. Food intake, blood pressure, blood glucose, and body weight measurements were taken and compared between OP rats and OR controls. The animals were then sacrificed by transcardial perfusion and fixed with 4% paraformaldehyde. Immunohistochemistry was performed on the coronal brainstem sections with polyclonal antibodies raised against TRPV3 and POMC. The sections were quantified using a microscope with reticule grid to measure the number of positive cells over a 200×200um area in the hypoglossal nucleus (HN) and medial nucleus tractus solitarius (mNTS). The results show that food intake and body weight were significantly reduced in OR rats compared to OP rats. (P<0.05, n = 7) POMC positive staining neurons were significantly reduced in the HN and (mNTS) in OP compared to OR rats. OP rats also have a significant increase in TRPV3 positive staining neurons in the HN and mNTS. We conclude that lower POMC and higher TRPV3 expressions in the HN and mNTS play a role in central regulation of food intake, which contribute to development of hyperphagia and obesity in OP rats. Supported by NIH (AT004620, and AT004504) and ADA 7‐07‐RA‐100 to S. Ma.