Caffeine will block the action of phosphodiesterase and thus the enzyme will not be activated to break down cAMP. Caffeine has some effects which are psychological in nature. At the cellular level, caffeine blocks the action of phosphodiesteerase. Phosphodiesterase is the one that break down the cAMP inside the cell.
the clear watery liquid that surrounds the brain and spinal cord and fills the four cavities or ventricles of the brain is known as CEREBROSPINAL FLUID