Related Experiment Video

Updated: Apr 30, 2026

Analytical Techniques for Assaying Nitric Oxide Bioactivity
11:28

Analytical Techniques for Assaying Nitric Oxide Bioactivity

Published on: June 18, 2012

17.7K

Induction of nitric oxide synthase by cyclic AMP in rat vascular smooth muscle cells

T Imai1, Y Hirata, K Kanno

  • 1Second Department of Internal Medicine, Tokyo Medical and Dental University, Japan.

The Journal of Clinical Investigation
|February 1, 1994
PubMed

Insights

Cyclic AMP (cAMP) upregulates the inducible nitric oxide synthase (iNOS) gene in rat vascular smooth muscle cells (VSMCs). This upregulation is linked to increased iNOS mRNA stability, influencing nitric oxide (NOx) production.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • Vascular smooth muscle cells (VSMCs) play a critical role in regulating vascular tone and function.
  • Nitric oxide synthase (NOS) enzymes, particularly inducible NOS (iNOS), are involved in NO production, impacting cardiovascular health.
  • Cyclic AMP (cAMP) is a key intracellular second messenger with diverse cellular functions, including the regulation of gene expression.

Purpose of the Study:

  • To investigate the effect of a membrane-permeable cAMP derivative, 8-bromo-cAMP, on iNOS gene expression and NOx synthesis in cultured rat VSMCs.
  • To elucidate the molecular mechanisms underlying cAMP-mediated iNOS regulation, including mRNA stability and protein synthesis.

Main Methods:

  • Measurements of nitric oxide (NO2-/NO3-, referred to as NOx) production.
  • Northern blot analysis to assess iNOS mRNA levels.
  • Use of NOS inhibitors (NG-monomethyl-L-arginine) and amino acid L-arginine.
  • Treatment with cAMP-elevating agents (cholera toxin, forskolin, 3-isobutyl-1-methylxanthine) and inhibitors of transcription/translation (actinomycin D, cycloheximide).

Main Results:

  • 8-bromo-cAMP significantly stimulated NOx production and increased iNOS mRNA levels in a time- and dose-dependent manner in rat VSMCs.
  • NOS inhibition blocked NOx production, with partial reversal by L-arginine.
  • Compounds that increase intracellular cAMP levels also stimulated NOx production.
  • Dexamethasone inhibited cAMP-induced NOx production and iNOS mRNA induction.
  • Actinomycin D and cycloheximide blocked cAMP-stimulated NOx production; actinomycin D abolished cAMP-induced iNOS mRNA, while cycloheximide caused superinduction.
  • cAMP-induced iNOS mRNA had a half-life of approximately 2 hours, while cycloheximide-induced iNOS mRNA showed no decay over 12 hours.

Conclusions:

  • cAMP upregulates the iNOS gene in rat VSMCs.
  • The observed superinduction of iNOS mRNA by cAMP is primarily due to increased mRNA stability.
  • These findings highlight a novel regulatory mechanism of iNOS expression by cAMP in vascular smooth muscle cells.

More Related Videos

Two-photon Imaging of Intracellular Ca2+ Handling and Nitric Oxide Production in Endothelial and Smooth Muscle Cells of an Isolated Rat Aorta08:08

Two-photon Imaging of Intracellular Ca2+ Handling and Nitric Oxide Production in Endothelial and Smooth Muscle Cells of an Isolated Rat Aorta

Published on: June 10, 2015

10.4K
Application of Genetically Encoded Fluorescent Nitric Oxide (NO•) Probes, the geNOps, for Real-time Imaging of NO• Signals in Single Cells08:32

Application of Genetically Encoded Fluorescent Nitric Oxide (NO•) Probes, the geNOps, for Real-time Imaging of NO• Signals in Single Cells

Published on: March 16, 2017

13.7K

Related Concept Videos

Paracrine Signaling01:21

Paracrine Signaling

Paracrine signaling allows cells to communicate with their immediate neighbors via secretion of signaling molecules. Such a signal can only trigger a response in nearby target cells because the signal molecules degrade quickly or are inactivated if not taken up. Prominent examples of paracrine signaling include nitric oxide signaling in blood vessels, synaptic signaling of neurons, the blood clotting system, tissue repair/wound healing, and local allergic skin reactions. Nitric oxide as a...
50.3K
Nitric Oxide Signaling Pathway01:28

Nitric Oxide Signaling Pathway

Nitric oxide (NO), an inorganic gas, acts as a potent second messenger in most animal and plant tissues. NO diffuses out of the cells that produce it and enters the neighboring cells to generate a downstream response. NO synthase (NOS) catalyzes NO production by the deamination of the amino acid arginine. There are three isoforms of NOS. Endothelial cells have endothelial NOS (eNOS), nerve and muscle cells have neuronal NOS (nNOS), and macrophages produce inducible NOS (iNOS) upon exposure...
5.3K
Smooth Muscle Contraction01:25

Smooth Muscle Contraction

Smooth muscle contraction is a complex process vital for various bodily functions, from maintaining blood vessel tension to facilitating the movement of food through the digestive tract. Unlike striated muscles, smooth muscle contraction begins more slowly and lasts longer.
The onset of contraction is triggered by an increase in calcium ions within the sarcoplasm, similar to the process in striated muscle. However, smooth muscles have a relatively smaller reservoir of the sarcoplasmic...
8.6K
Antihypertensive Drugs: Vasodilators01:23

Antihypertensive Drugs: Vasodilators

Vasodilators, primarily affecting the smooth muscles within arterial and venous walls, are commonly used for hypertension treatment. Medications such as minoxidil and hydralazine primarily target arteries and arterioles, while sodium nitroprusside acts on arterioles and venules. Minoxidil, functioning as a prodrug, is metabolized by hepatic sulfotransferase into its active form, minoxidil sulfate, after oral administration. This metabolite binds to the sulfonylurea receptor (SUR) component of...
2.5K