Frederick Douglass changed his name in order to escape the identity that given by his old master when he's still a slave.
Back then, his names had several similarities with pretty famous figure and he did not want to convey the false mistakes that they're in any way related from one another.
I believe the answer is: Nitric oxide
<span>Nitric oxide could be synthesized on demand, because it is considered to be membrane permeant that cannot be stored. Calcium influx through </span><span>The N-methyl-D-aspartate </span>receptor activates nitric oxide synthase (NOS), which synthesizes Nitric oxide from L-arginine which allow it <span> to act as a retrograde messenger from the dendrite to the terminal button. </span>
When a bill is passed by both houses of Congress, it is then sent to the President.