NADIA COETZEE

Default profile image
----------

Blog #2.4

18 Sep 2021, 12:59 Publicly Viewable
  • What do you understand by the term “endothelium-dependent” vasodilation?  Explain.

This means that these agents increase intracellular Ca²⁺ in endothelial cells which leads to synthesis of NO. NO diffuses into vascular smooth muscle and leads to vasorelaxation.

  • 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 enzymes are enzymes that are constantly being made whether it is need or not, they also stay is one area, where Inducible enzymes is made when a substance is present. Their effects is smaller.

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

Sepsis is caused by an infection. Edotoxin components induce synthesis of iNOS in smooth muscle cells, endothelial cells and more, which leads to widespread generation of NO, can lead to hypotension, shock and in some cases death.

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

Nitric Oxide (NO).

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

NOS inhibitors are releases which binds to L-arginine form which NO is synthesised from. This prevents arginine to bind to the three NOS enzymes, which leads to decrease concentration of NO.

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

A Stimulus can activate the inflammatory mediators, which result in increase in iNOS levels. The vasodilatory effects of NO and effects of COX II plays a role in inflammation and causes red skin, increased vascular permeability which can lead to oedema. Although a disadvantage is that excessive production of NO, causes tissue damage, diseases, asthma and lesions.

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

In stroke, amyotrophic lateral sclerosis, and Parkinson disease, where excessive NO is involved.