NITRIC OXIDE

Question 1

nitric oxide relaxes vessels

Answer 1

Ach binds to M3 -> increses the ic Ca++ content -> activates NOS -> NO synthesis incresaes -> NO diffuses to adjacent vessels smooth muscle cells -> activâtes guanylate cyclase -> incrase of cGMP whoch activâtes PKG -> phosphorylates L-type Ca++ ATPase and Ca++ pump -> ic Ca++ decrease -> relaxation of smooth muscle

Question 2

M2

Answer 2

slow the heart rate/the normal sinus rythm = decreses chronotropy
slow the conduction velocity of SA nodal cells= decreased inotropy
slow the contraction force of the atrial cardiac muscle= decreased dromotropy (also a little bit of ventricules)

after a synpathetic activation Gi type receptor -> decrease cAMP + inhibition of voltage gated Ca++ channel + increased efflux of K+ -> inhibitory effect

Question 3

NO characteristic

Answer 3

small, lipid soluble and unchrged
can act on nearby neuron
short half-life so no need to eliminate it or reuptake it
highly reactive with protein, lipids and other free radicals

Question 4

location of NO in brain

Answer 4

bulbus olfactorius
cortex, striatum
cerebellum: granule and basket cells

Question 5

Membrane Guanylate Cyclase

Answer 5

ANF produces by Atrial myocytes
ANF binds to its receptor on GC and activâtes and prdocuces cGMP
cGMP causing vasodilation

and also Na+ excretion

secretion vasopressine and aldosterne inhibited

Question 6

Soluble Guanylate Cyclase

Answer 6

in the cytosol not related to the receptor
activated by Nitrogen contaning compounds
smooth muscle relaxation