Which of the following statement is true about nitrates

Nitrates acts by releasing nitric oxide which increases cGMP that cause dephosphorylation of myosin light chain kinase. These are preferential dilators of venules because glutathione reductase (enzyme that release NO from nitrates) is principally present at these sites. These agents are smooth muscle relaxants and can be used in colic and achlasia cardia Refer kDT 6/e p523