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NBME 21 Answers

nbme21/Block 1/Question#48

A 44-year-old man is admitted to the hospital ...

Increasing cGMP

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submitted by divya(28),

increase in cAMP (Gs) - beta2 - vasodilation

decrease in cAMP (Gi) - alpha2 - vasoconstriction

increase in IP3 DAG (Gq) - alpha1 - vasoconstriction

increase in cGMP - M3 - NO induced vasodilation



simple rule of thumb is

Calcium --> vasoconstriction (smooth muscle constriction) -- > must be Gq (alpha 1, v1)

rise in cAMP and cGMP both vasodilation (cAMP by inhibiting MLCK, cGMP by activating MLCP) so whoever causes vasodialation must increase either. cGMP is niche (NO, ANP) so most of the time it is rise in cAMP --> must be Gs (beta 2)

only exception is M3 it rises calcium (Gq) but in endothelial cells , not vascular smooth m. cells, so NO produced and causes vasodialation via rise in cGMP (again!)

+/- b1ackcoffee(0),


HTN emergency, Sodium Nitroprusside. Unlike hydralazine a balanced vasodilator (vein = arteriol)

sympathetikey  Well then, I guess we should just forget about our old pals the Alpha-2 agonists. Good call. I didn't even see that this was hypertensive emergency. Dumb on my part. +  
zup  so yea clonidine would be used for hypertensive urgency, but this guy is over 180 (210) so they have to use something like hydralazine or nitroprusside both will increase cGMP +  
whoissaad  Drugs used to treat HTN emergency: Nitroprusside Labetolol Nicardipine Clevidpine Fenoldapam Clonidine +6