Spontaneously Hypertensive Rats Are Highly Vulnerable to AMPA-Induced Brain Lesions

In this study, the experimenters were curious if there was a difference in the brain tissue in spontaneously hypertensive rats (SHRs) and normotensive rats (WKYs) that formed hypertension(R-WKYs). They were looking specifically if the SHRs or WKYs contained damaging/killing neurons from the over activation of glutamate receptors. The 2 glutamate receptors they looked at were NMDA or AMPA. These receptors were compared to see if the vulnerability of the brain tissue between the SHRs and WYKs might contribute to increased brain damage after ischemia (loss of blood to brain/heart). They induced ischemia by the intraluminal technique and a laser Doppler flowmetry probe to locate the exact area of ischemia and occlusion (blocking of an artery).  After an ischemic event, an increased release of glutamate caused over activation of NMDA and AMPA triggering neuronal death. They found that the SHRs had significant increase in dead tissue due to inadequate blood flow and higher mortality rate (63% SHRs to 17% WKY) in comparable aged WKY rats. This provides evidence that SHRs have sensitivity to AMPA, and not the NMDA. But they proved that it is not fully dependent on the level of arterial hypertension, it is also caused by the increased phosphorylation of GluR1 leading to a high vulnerability to AMPA-induced brain damage in the SHRs.