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

Abstract

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-1 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-1 DBM, 18% 12 h after 6 mmol kg-1 DBM and 17% in the CO-exposed group. The sesame oil controls exhibited no elevation in COHb. The BT dropped by ca. 1 degree 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 degree C and 1.2 degree C after 6 h in the 3 and 6 mmol kg-1 DBM groups, respectively, and by 0.9 degree 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.(ABSTRACT TRUNCATED AT 250 WORDS)