Gender differences in the renal NMDA receptor in rats.

Abstract

NMDA is a “glutamate” receptor found throughout the brain. It is involved in plasticity and learning. Over stimulation may cause apoptosis and cell death during ischemic insults such as stroke. We have previously reported functional n-methyl-d-aspartate (NMDA) receptors in rat kidney (J. Am Soc Neph 13:, 2002). These calcium channel receptors are independent of renal innervation. NMDA is required for glycine-induced increase in glomerular filtration rate and renal plasma flow, and also for the increases in oxygen consumption and proximal tubule sodium transport. There are several NMDA subtypes present in the brain. These subtypes may vary by age and sex of the animal. In this study we measured the NMDA subtypes, NR1 and NR2A-D in rat kidneys by Western Blot. In addition, we compared male to female rat kidneys. We found all receptor subtypes are present in rat kidney tissues. In addition, we found the NR2A subunit to be significantly lower in female rats compared to males. The other subunits were not different. This is in agreement with studies finding gender differences in location of the NR2A subunit of the NMDA receptor in the rat brain. These studies reiterate the importance of the renal NMDA receptor in kidney function and point to another gender-dependent difference in renal regulation. Funded by NIH NIDDK RO-1 DK 62831.