<prompt> The substance that is a vasodilator elsewhere but causes vasoconstriction in kidneys afferent aeriole is:Nitric oxideAdenosineBradykininEndothelin  <response>: Adenosine has 2 receptors - A1 A2 A2 vasodilation elsewhere A1 vasoconstriction kidney Adenosine is a ligand, pa of the tubuloglomerular feedback. Macula densa cells sense the Na level in tubular fluids. Excess Na reaching macula densa cells Na K ATPase pump in basolateral membranes transpo Na K by degrading ATP Adenosine formed as a by product Adenosine acts as a ligand on the A1 receptors of afferent aeriole Constriction of afferent aerioles 