Determination of carbon monoxide (CO) in rodent tissue: Effect of heme administration and environmental CO exposure
ABSTRACT Carbon monoxide (CO), produced endogenously during heme degradation, is considered a messenger molecule in vascular and neurologic tissues. To study this role, it is important to determine CO concentration in target tissues pre- and post-perturbations. Here, we describe a sensitive and reproducible method, which is linear and accurate, and provide some examples of its application for quantitation of CO concentrations in tissues pre- and post-perturbations. Tissues from adult rats and mice were sonicated (20% w/w), and volumes representing 0.04-8 mg fresh weight (FW) were incubated at 0 degrees C for 30 min with sulfosalicylic acid. CO liberated into the headspace was quantitated by gas chromatography. Tissue CO concentrations (mean+/-SD, pmol CO/mg FW) were as follows: blood (47+/-10, 45+/-5), muscle (4+/-4, 10+/-1), kidney (5+/-2, 7+/-2), heart (6+/-3, 6+/-1), spleen (11+/-3, 6+/-1), liver (4+/-1, 5+/-1), intestine (2+/-1, 4+/-2), lung (2+/-1, 3+/-1), testes (1+/-1, 2+/-1), and brain (2+/-1, 2+/-0) in untreated rat (n=3) and mouse (n=5), respectively. Between the rat and the mouse, only CO concentrations in the muscle and spleen were significantly different (p0.05). Endogenous CO generation, after administration of heme arginate to mice (n=3), increased CO concentrations by 0-43 pmol/mg FW. Exposure of mice (n=3) to 500 ppm CO for 30 min yielded significantly elevated CO concentrations by 4-2603 pmol/mg FW in all tissues over the native state. While blood had the highest CO concentration for all conditions, muscle, kidney, heart, spleen, and liver, all rich in hemoglobin and/or other CO-binding hemoproteins, also contained substantial CO concentrations. Intestine, lung, testes, and brain contained the lowest CO concentrations.
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ABSTRACT: The discovery of the biological effects of carbon monoxide (CO) in recent years strongly suggests that CO could find applications as a therapeutic agent. CO is a highly toxic gas when used at industrial doses, due in part to its binding affinity to hemoglobin. Since hemoglobin binds CO with the highest affinity in vivo, it also constitutes a major barrier to the delivery of CO to tissues in need of therapy. A method of delivering CO that can bypass hemoglobin is the use of pro-drugs or CO carriers, called CO-releasing molecules (CO-RMs) that become activated and release CO in tissues in need of treatment. Organometallic carbonyl complexes are best suited to play the role of CO carriers, and indeed the natural CO carrier molecules hemoglobin and myoglobin belong to this class of chemical compounds. Here we describe the preparation of novel molybdenum CO-RMs of general formula Mo(CO)3(CNCR′R″CO2R‴)3 (R′, R″ = H, Me, iPr, CH2Ph, CO2Li, −CH2CH2–, −CH2(CH2)3CH2–; R‴ = H, Li), which present favorable druglike characteristics, have low toxicity, and demonstrate specific CO delivery to the liver in the treatment of acetaminophen (APAP)-induced acute liver failure in mice.Organometallics 07/2012; 31(16):5810–5822. DOI:10.1021/om300360c · 4.25 Impact Factor
01/2013; 9(1-4). DOI:10.1515/irm-2013-0003
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ABSTRACT: Background: Metabolic syndrome is a collection of ailments resulting in a higher risk of cardiovascular disease and type II diabetes mellitus. It also results in prolonged endothelial dysfunction which promotes hypertension. Objective: The current study examines the acute effect of carbon monoxide (CO) inhibition and nitric oxide (NO) stimulation in septal coronary arteries. Methods: These studies were conducted in inactin anesthetized obese and lean Zucker rats (13-14 weeks of age). Coronary arteries were isolated from obese and lean Zucker rats and in vitro experiments were conducted. Isolated coronary arteries were pre-treated with chromium mesoporphyrin (CrMP) which is a heme oxygenase inhibitor and L-arginine, a NO precursor. Results: Blood pressure, non-fasting blood glucose, HBCO, CO levels and Arginase I expression were higher in obese Zucker rats (ZR) as compared to the lean (L) group. Obese ZR had higher body, kidney and heart weights as compared to the LZR. Acetylcholine induced vasodilation was greatly attenuated in Obese ZR compared to the lean group. No differences in the diameters of the septal coronary artery were observed in both groups when treated with CrMP. However, pretreatment with L-arginine, abolished the differences between the groups. Conclusion: This study demonstrates the potential of NO induction to improve coronary blood flow during metabolic syndrome induced endothelial dysfunction, where alterations in CO levels appeared to have no significant coronary effects.03/2014; 2(1):8. DOI:10.14419/ijm.v2i1.1941