Question

Can the compensatory parasympathetic response stop vasoconstriction? why or why not?

Also, treatment fir autonomic disreflexia is removal of the painful stimulus that started the disreflexia in the first place. if that doesnt work, drugs that alter the autonomic nervous system (agonists and antagonists) must be used. suggest a drug mechanism that might work to stop the disreflexia (you dont need a name, just describe its action)

THANK YOU for helping a tired, brain dead student :')

Answer 1

Can the compensatory parasympathetic response stop vasoconstriction? why or why not?

Whole mechanism is explained in photos . Dear student...

suggest a drug mechanism that might work to stop the disreflexia...

Failure of proper management of autonomic dysreflexia can lead to sever hypertension causing subarachnoid hemorrhage, intracerebral hemorrhage , pulmonary edema etc. Which all are life threatening conditions.
Treatment is first make the patient sit up so that due to orthostatic hyptension BP falls a little.. this is because in sudden sitting or standing position there is venous pooling decrease the venous return causing decrease in Heart rate and hence fall inBP......
Next is look for precipitating factors and remove it...    factors like Bladder distention

Urinary tract infection

Calculus

Cystoscopy/instrumentation

Urodynamic study

Epididymitis or scrotal compression

Bowel distention

Fecal impaction

Bowel instrumentation/colonoscopy

Reflux or gastritis etc. And remove it ...

, the best antihypertensive medications to use in this situation have a rapid onset and short duration of action. Nitrates and, especially, nifedipine (immediate- release form) appear to be the most commonly used medications.....

Nitrates Pharmacokinetics is -
It is activated by Aldheyde dehydrogenase into NO..
This stimulates Guanylate cyclase in smooth muscle of blood vessel..
There is increase in cGMP leading to activation of protein kinase that
Phosphorylates MLCK leading to its inhibition..
This results in smooth muscle relaxation and hence vasodilation and hence fall in BP....

But if autonmoc dysreflexia is precipitated due to Viagra then nitrates are contraindicated because ...
Viagra contains Sildenafil that is PDE-5 inhibitor that Inhibits breakdown of cAMP and increase its accumulation which bitslef causes vasodilation and hence hyptotension...
If nitrates and sildenafil used together it will cause fatal hypotension leading to death...