1: Am J Physiol Heart Circ Physiol. 2001 Jan;280(1):H483-8. 

Real-time measurements of endogenous CO production from vascular cells using an
ultrasensitive laser sensor.

Morimoto Y, Durante W, Lancaster DG, Klattenhoff J, Tittel FK.

Rice Quantum Institute, Rice University, Houston, Texas 77251, USA.
moyan@interlink.or.jp

Carbon monoxide (CO) has been implicated as a biological messenger molecule
analogous to nitric oxide. A compact gas sensor based on a midinfrared laser
absorption spectroscopy was developed for direct and real-time measurement of
trace levels (in approximate pmol) of CO release by vascular cells. The
midinfrared light is generated by difference frequency mixing of two
nearinfrared lasers in a nonlinear optical crystal. A strong infrared absorption
line of CO (4.61 microm) is chosen for convenient CO detection without
interference from other gas species. The generation of CO from cultured vascular
smooth muscle cells was detected every 20 s without any chemical modification to
the CO. The sensitivity of the sensor reached 6.9 pmol CO. CO synthesis was
measured from untreated control cells (0.25 nmol per 10(7) cells/h), sodium
nitroprusside-treated cells (0.29 nmol per 10(7) cells/h), and hemin-treated
cells (0.49 nmol per 10(7) cells/h). The sensor also detected decreases in CO
production after the addition of the heme oxygenase (HO) inhibitor tin
protoporphyrin-IX (from 0.49 to 0.02 nmol per 10(7) cells/h) and increases after
the administration of the HO substrate hemin (from 0.27 to 0.64 nmol per 10(7)
cells/h). These results demonstrate that midinfrared laser absorption
spectroscopy is a useful technique for the noninvasive and real-time detection
of trace levels of CO from biological tissues.

PMID: 11123266 [PubMed - indexed for MEDLINE]