• What do you understand by the term “endothelium-dependent” vasodilation?  Explain.

This is an increase in blood flow which stimulates endothelium-dependent vasodilation by increasing shear stress on the endothelium. 

• When we talk about the NOS enzyme, what is meant by “constitutive” and “inducible” enzymes and what are the pathological and physiological implications thereof?

Constitutive - an enzyme that is formed at a constant rate and in an constant amount in a given cell.

Inducible - is an enzyme that is normally present in minute quantities within a cell but whose concentration increases dramatically when a substrate compound is added. 

• Explain how NO contributes to the fatal pathology of septic shock.

Nitric Oxide synthesis is dysregulated exaggerated production leading to cardiovascular dysfunction, bioenergetic failure and cellular toxicity

Excessive formation of NO is a major factor involved in the pathologic vasodilatation and tissue damage observed.

• Which autacoids’ mechanism of action depends on effects on the guanylyl cyclase-cGMP system?

NO - Nitric Oxide.

• NO may be toxic to the cell.  Which mechanisms are available to the body to counter this detrimental effect of NO?

It can be inactivated by reacting with O₂ (Oxygen) to form nitrogen dioxide. It also reacts hemoproteins which oxidize NO to Nitrates.

• Name a way in which NO can act pro-inflammatory.  Give examples of where it will have advantages or disadvantages.

It is considered a proinflammatory mediator because it induces inflammation due to overproduction in abnormal situations.

• In which possible neurological and psychiatric diseases is NO involved? 

Parkiinson disease and stroke