NMDA Receptor Subunit Expression in the Paraventricular Nucleus of the Spontaneously Hypertensive and Pregnant Rat

Sympathoexcitation is characteristic of cardiovascular disease and pregnancy. Studies show that the paraventricular nucleus of the hypothalamus (PVN) is a key area mediating sympathetic nerve activity (SNA). In hypertension and heart failure (HF), alterations in glutamatergic activity within this nucleus contribute towards sympathoexcitation. Furthermore, HF studies have revealed that the expression of the NMDAR1 subunit is increased in the PVN. We hypothesised that NMDA receptor plasticity is involved in the increased SNA observed in hypertension and pregnancy. PVN micropunches were subjected to immunoblotting and probed for either the NR1 or NR2A subunit and quantified based on optical densitometry. We have confirmed the presence of the NR1 and NR2A subunits within the PVN of control, hypertensive and pregnant animals and observed expression levels of these subunits within the PVN of hypertensive and pregnant animals do not change. This is the first study to examine NMDA receptor subunit expression in the PVN of hypertensive and pregnant animals and suggests that the NR1 and NR2A subunits do not contribute to the sympathoexcitation observed in these states. Work supported by the BBSRC.