Does sympathetic stimulation lead to an increase or decrease in GFR?

Sympathetic stimulation typically leads to a decrease in the glomerular filtration rate (GFR). This response is part of the body's overall reaction to stress, known as the "fight or flight" response. When the sympathetic nervous system is activated, it causes constriction of the afferent arterioles that supply blood to the glomeruli in the kidneys. As these arterioles constrict, less blood flows into the glomeruli, resulting in a reduced filtration rate.

Additionally, during sympathetic activation, blood is redirected to vital organs and muscles, and the kidneys receive less blood supply prioritized for survival functions. This reduction in renal blood flow further contributes to the decrease in GFR. Although there may be some variability in responses under different physiological conditions, the general outcome of sympathetic stimulation consistently results in a lower GFR.