Dibromomethane and carbon monoxide in the rat: Comparison of the cardiovascular and metabolic effects

✍ Scribed by Michael S. Fozo; David G. Penney

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 459 KB
• Volume: 13
• Category: Article
• ISSN: 0260-437X
• DOI: 10.1002/jat.2550130213

✦ Synopsis

The goals of this study were to examine the cardiovascular and metabolic responses to a dihalogenated methane and to compare them to inhaled CO. One group of male Sprague-Dawley rats received an i.p. injection of either 3 or 6 mmol kg-' dibromomethane (DBM) diluted 1:3 with sesame oil. Measurements of carboxyhemoglobin (COHb), rectal body temperature (BT), heart rate, systolic blood pressure (BP) and blood glucose and lactate concentrations were made at times 0, 30, 60, 120, 240, 360, 480, 600, 720, 840, 1020, 1440 and 1680 min. A second group of rats received only sesame oil and was tested in the same manner. A third group of rats breathed 225 ppm CO for 120 min before being tested. Peak COHb levels were 16% 8 h after 3 mmol kg-' DBM. 18% 12 h after 6 mmol kg-' DBM and 17% in the CO-exposed group. The sesame oil controls exhibited no elevation in COHb. The BT dropped by ca. 1°C in both the DBM-and CO-exposed rats, while there was no BT change in the sesame oil controls. The BT dropped by 1.0"C and 12°C after 6 h in the 3 and 6 mmol kg-' DBM groups, respectively, and by 0.9"C after 120 min in the CO-exposed group. The CO-exposed rats displayed a 12 mmHg decrease in systolic BP, while both doses of DBM failed to produce any significant BP change. The BP in the sesame oil controls remained constant. There were no significant changes in heart rate or in blood glucose or lactate in any of the experimental groups. The lack of a BP response in the DBM rats may be due to DBM interferring with the rat's normal response to CO, or to the effects of dissolved CO vs. COHb. Dibromomethane uptake results in the development of significant and prolonged COHb saturation, at a level similar to that resulting from inhalation of 225 ppm CO. Although BT regulation is impaired, DBM appears not to have significant effects on BP, heart rate or blood glucose and lactate concentrations.