Wat beteken die term “endotelium-afhanklike” vasodilatasie vir jou? Verduidelik.

The term refers to the action of the increase of intracellular calcium levels in endothelial cells, leading to NO synthesis and NO then diffuses to the vascular smooth muscle leading to the effect of vasodilatation/vasorelaxation.

 

As ons praat van die NOS-ensieme, wat beteken “konstitueel” en “geïnduseerde” ensieme, en wat is die patologiese en fisiologiese implikasies hiervan?

Constitutive enzymes are synthesized at a constant level and also constant amounts. These enzymes are always produced whether or not a suitable substrate is present or regardless of its metabolic state and these enzymes are regulated by calcium.

Inducible enzymes are not regulated by calcium, the presence of an inducer leads to an increase in gene expression. When substrates are added, it results in a major increase of this enzyme leading to iNOS accumulation and produces a great amount of NO.

 

Verduidelik hoe NO tot die noodlottige patologie van septiese skok bydra.

Endotoxin components from the bacterial wall along with endogenously generated tumor necrosis factor and other cytokines induce the synthesis of iNOS in macrophages, neutrophils, T cells as well as hepatocytes, smooth muscle cells, endothelial cells and fibroblasts. This widespread generation on NO results in exaggerated hypotension, shock and in some case death.

 

Watter outakoïede se meganisme van werking berus op effekte op die guanilielsiklase-cGMP-stelsel?

Nitric Oxide (NO)

 

NO kan vir die sel toksies wees.  Watter maniere het die liggaam om hierdie nadelige effek van NO teen te werk?

NO can react with hemoglobin which leads to S-nitrosylation of hemoglobin, resulting in the transport of nitric oxide throughout the vasculature.

NO can be inactivated by reacting with O2 to form nitrogen dioxide.

NO can also react with heme and hemoproteins so that NO can be oxidized to nitrate.

 

Noem ‘n manier hoe NO pro-inflammatories kan optree.  Gee voorbeelde waar dit voor- of nadele sal hê

NO is considered as a pro-inflammatory mediator that induces inflammation in response to abnormal situations meaning that NO helps to regulate the immune system.

Advantages: NO appears to play an important protective role in the body via immune cell function. When foreign antigens are present, TH1 cells respond by synthesizing NO and the importance of this action is demonstrated by the impaired protective response to injected parasites in animal models after inhibition of iNOS.

Disadvantages: Prolonged or excessive NO production can exacerbate tissue injury in both acute and chronic inflammatory conditions.

 

In watter moontlike neurologiese en psigiese siektes is NO betrokke?

Parkinson’s disease, stroke, amyotrophic lateral sclerosis.