Nitric Oxide and Its Biological Functions

Nitric oxide (NO●) is a _____ _____ with a half-life of a few seconds seconds.

free radical

One function of NO● is __, which is the relaxation of blood vessels.

vasodilation.

NO● plays a key role in __ and inflammation.

immunity.

Constitutive NOS enzymes include neuronal NOS (nNOS or NOS1) and __.

endothelial NOS (eNOS or NOS3).

Inducible NOS (iNOS or NOS2) is induced in immune cells by __.

cytokines.

Sustained production of NO● can lead to __ effects.

indirect.

NO● activates guanylyl cyclase (GC), leading to increased levels of __.

cyclic guanosine monophosphate (cGMP).

In cGMP

_____ acts as a second messenger in the signaling process.

cGMP

Phosphodiesterases (PDEs) degrade cGMP to __, regulating its signaling.

GMP.

Nitrodilators include __ and sodium nitroprusside.

inhaled NO● gas.

Organic nitrates like Nitroglycerin are metabolized into active __.

NO●.

PDE inhibitors were initially researched for treating __ and pulmonary hypertension.

angina.

Sildenafil (Viagra) has a half-life of __ hours.

4.

Tadalafil (Cialis) has a longer half-life of __ hours.

17.5.

Inhibition of PDE5 leads to sustained levels of __.

cGMP.

NO● plays a role in immunity by increasing iNOS to produce __ in response to infections.

NO●.

Excess free radicals can cause __ under chronic inflammatory states.

tissue damage.

Nitric oxide can yield byproducts that modify proteins via __ nitration.

tyrosine.

Interactions with lipids and DNA can cause potential __.

damage.

Nitrosation can form nitrosamines, which are potential __.

chemical carcinogens.

Peroxynitrite (ONOO-) is formed by the interaction of NO● and __.

superoxide.

Peroxynitrite can initiate __, damaging cellular components.

lipid peroxidation.

Nitrotyrosine is a marker of __ stress caused by oxidative damage.

oxidative.

The mechanisms of NO● signal transduction include the activation of __ protein kinases.

cGMP-dependent.

NO● is critical for protecting organs such as the liver from __ damage.

ischemic.

Complex roles of NO● in immunity include killing or inhibiting the growth of __.

pathogens.

NO● signaling involves binding to the iron of __-containing proteins.

heme.

Increased cGMP affects signaling pathways for smooth muscle __.

relaxation.

Low levels of NO● can lead to __ production in immune cells.

higher, sustained.

NO● has functions in __, which is critical for communication between nerves.

neurotransmission.

Sustained cGMP signaling is terminated by the action of __.

phosphodiesterases (PDEs).

PDEs vary in __ across tissues, influencing side effects of inhibitors.

distribution.

An unsafe drop in blood pressure may occur due to __ vasodilation.

pulmonary.

Blurred vision from PDE inhibitors is due to PDE6's involvement in __.

retinal visual signal transduction.

NO● modulates neuronal stimulation through __ and nNOS.

eNOS.

Chemical pathways activated by NO● contribute to both __ and pathology.

defense.

NO● can diffuse into __, potentially causing damage.

DNA.

Interaction with __ radicals can lead to DNA damage and mutagenic changes.

oxidized guanine.

Nitric oxide's role in signaling can include both beneficial and __ effects.

detrimental.

NO● signaling is involved in the therapeutic use for treating __ pectoris.

angina.

Therapeutics using NO● include __ and sodium nitroprusside.

inhaled NO● gas.

The core component of NO● signaling pathways primarily involves __.

cGMP.

NO●'s role in the body is associated with __ cascades and their activation.

signal transduction.

NO● signaling pathways regulate smooth muscle __ and relaxation.

contraction.

One therapeutic use of NO● is in the treatment of __ heart failure.

congestive.

The production of NO● is essential for the function of the __ system.

immune.

Inducible NOS (iNOS) is more commonly found in __ cells during immunological responses.

immune.

Nitric oxide's unique characteristics include being a __ in biological systems.

free radical.

CHronic inflammation can lead to a complex interplay between NO● and __ damage.

tissue.

In therapy, PDE inhibitors increase the concentration of cellular __.

cGMP.

Sodium nitroprusside is an example of a therapeutic __ that utilizes NO●.

nitrodilator.

Tyrosine nitration by NO● can result in markers such as __.

3-nitrotyrosine.

Signal transduction involving NO● primarily influences __ signaling pathways.

cellular.

NO●'s interaction with biological targets leads to __ cellular responses.

various.

The mechanism of action for NO● includes the stimulation of __ in targeted cells.

enzyme activity.

Histological analysis of tissues can reveal the presence of __ due to NO● signaling.

nitrotyrosine.

Therapeutics utilizing NO● often focus on enhancing __ effects in smooth muscle.

relaxation.

NO● produced in response to pathogens via iNOS enhances __ function.

immune.

The breakdown of cGMP by phosphodiesterases must be finely regulated to maintain __ responses.

physiological.

Through neurotransmission processes, NO● supports neuronal __ and function.

communication.

Excessive levels of NO● can lead to __ effects under chronic conditions.

detrimental.

NO● acts through direct binding to target proteins to promote __ signaling responses.

cellular.