Nitric oxide or nitrogen monoxide (NO) is a gas. It is highly reactive and is involved in many chemical reactions. NO is also a toxic air pollutant produced by automobile exhaust and power plants. However, it has many physiological functions and is an important signaling molecule in the body of mammals including humans.
Some of the physiological functions of nitric oxide include:
- Relaxation of the smooth muscle in the walls of the arterioles during each systole to permit the surge of blood to pass through easily
- Inhibition of the aggregation of platelets and prevents inappropriate clotting from interfering with blood flow
- Increases the rate of filtration and urine formation by increasing blood flow through the glomeruli
- Mediation of penile erection during sexual excitation is mediated by NO released from nerve endings close to the blood vessels of the penis
- Mediation of the wavelike motions of the gastrointestinal tract during peristalsis
- Inhibition of the contractility of the smooth muscle wall of the uterus during pregnancy
- Inhibition of the inflammation in blood vessels
- Stimulation of the secretion from several endocrine glands
- Acts as a neurotransmitter for some motor neurons of the parasympathetic branch of the autonomic nervous system
- Helps in the killing of engulfed pathogens such as bacteria within macrophages
Chemiluminescence detectors are normally used to detect nitric oxide in air, while Clark-style electrodes and a suitable electrochemical meter are most often used for measurements in solution. Both types of detectors can be obtained in models that are compatible with the PowerLab data acquisition unit. These meters should have an 'analog voltage output'. Nitric oxide can also be made to react with chemicals to form highly-coloured dyes which can be detected via spectroscopic methods.
Chemiluminesence MethodPowerLab can be used with the Sievers Nitric Oxide Analyzer which can be used to detect nitric oxide in exhaled air.
Electrochemical MethodPowerLab can be used for NO measurements in a solution with electrochemical meters and electrodes made by Diamond General, Innovative Instruments, Inter Medical, and WPI Inc. The LabChart software used together with the PowerLab to record the signal provides non-linear, multiple point calibration of the signal, which is facilitated by using the
Multipoint Calibration LabChart Extension (Win or Mac).
Absorbance MethodNitric oxide concentration can be determined spectroscopically with the Eicom ENO-10 NOx analysis system. Nitric oxide is measured by the reaction of an amine to produce a coloured dyestuff which is then analyzed by an absorbance chromatography detector.. This method is thought to have much greater sensitivity than the chemiluminesence method. Samples can be obtained either
in vitro or
in vivo by tissue microdialysis.
Note: PowerLab can simultaneously monitor output from other meters. See the following application pages for more information:
•
Oxygen Concentration•
CO2 and NH3•
Respiratory Gas Analysis•
ECG•
Blood Pressure - Intravascular
LabChart
LabChart software (for Windows and Macintosh) combines the familiar simplicity of a traditional strip chart recorder with the powerful analysis features of a digital acquisition system. LabChart software and a PowerLab data acquisition unit provide data integrity, easy selection of hardware settings, powerful online and offline analysis, procedure automation, seamless extraction of experimental data and flexible display options. Acquisition and analysis capabilities can be further increased with LabChart Extensions and LabChart Modules. LabChart Modules are available as part of LabChart Pro and LabChart Extensions are free for download from the website for existing LabChart users.
Electrodes can be calibrated using the Units Conversion feature of the software.
GLP and 21 CFR Part 11For those researchers working within a laboratory requiring GLP and 21 CFR Part 11 compliance the
GLP Client and GLP Server are available for use with LabChart (Windows only) and PowerLab data acquisition systems. For more information, visit the
Good Laboratory Practice application page or contact your nearest ADInstruments representative.
PowerLab Data Acquisition Systems The PowerLab is a high-performance data acquisition unit suitable for a wide range of research applications. Typical applications include human and animal physiology, pharmacology, neurophysiology, biology, zoology, biochemistry, and biomedical engineering. Units are capable of recording at speeds of up to 400 000 samples per second continuously to disk (aggregate), and are compatible with instruments, signal conditioners and transducers supplied by ADInstruments, as well as many other brands. In addition to standard single-ended BNC inputs, 4 differential Pod ports are also available for direct connection of Pod signal conditioners and appropriate transducers. These systems include: