Final answer:
Neural control of GFR is mediated by sympathetic neurons that innervate alpha receptors on vascular smooth muscle, resulting in vasoconstriction.
Step-by-step explanation:
The neural control of Glomerular Filtration Rate (GFR) is mediated by sympathetic neurons that innervate α (alpha) receptors on vascular smooth muscle, causing vasoconstriction. The release of the neurotransmitter norepinephrine from these neurons leads to the constriction of the afferent arterioles supplying the kidney's nephrons, thereby reducing GFR under stress or conditions requiring a redistribution of blood flow to more vital organs. This adjustment is part of the body's broader regulation of blood pressure and fluid balance, and it is controlled by the autonomic nervous system.