Canadian journal of physiology and pharmacology
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Can. J. Physiol. Pharmacol. · Sep 1989
Effects of hyperbaric oxygen in circulatory shock induced by splanchnic artery occlusion and reperfusion in rats.
We studied the effects of hyperbaric oxygen in a severe model of circulatory shock induced by occlusion and reperfusion of major splanchnic arteries (splanchnic artery occlusion (SAO) shock). Pentobarbital-anesthetized rats subjected to total occlusion of the superior mesenteric and the celiac arteries for 40 min developed a severe shock state, resulting in a uniformly fatal outcome after release of the occlusion. Exposure to hyperbaric oxygen at 2 ATA (atmosphere absolute) (1 ATA = 0.1 MPa) was initiated immediately after reperfusion. ⋯ Treatment with hyperbaric oxygen attenuated the increase in plasma activities of the lysosomal hydrolase cathepsin D (p less than 0.05), and diminished the increase of hematocrit (p less than 0.01 from untreated shock rats). Splanchnic occlusion shock rats treated with hyperbaric oxygen also exhibited a significantly higher survival rate than the untreated shock group (77 vs. 0%, respectively; p less than 0.01). Our results suggest that the beneficial effects of exposure to hyperbaric oxygen immediately after reperfusion of the splanchnic region outweigh its possible deleterious effect.
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Can. J. Physiol. Pharmacol. · Sep 1989
ReviewNew perspectives on cocaine addiction: recent findings from animal research.
Research with laboratory animals has provided several insights into the nature of cocaine abuse and addiction. First, the nature of drug addiction has been reevaluated and the emphasis has shifted from physical dependence to compulsive drug-taking behavior. Second, animal studies suggest that cocaine is at least as addictive as heroin and possibly even more addictive. ⋯ Fifth, although the biological consequences of repeated cocaine self-administration on central nervous system functioning are poorly understood, preliminary findings suggest that intravenous cocaine self-administration may decrease neural functioning in this brain reward system. This has important clinical implications because diminished functioning of an important brain reward system may significantly contribute to relapse into cocaine addiction. These and other findings from experimentation with laboratory animals suggest new considerations for the etiology and treatment of drug addiction.
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Can. J. Physiol. Pharmacol. · Sep 1989
Positive hemodynamic interaction between amrinone and diltiazem in anesthetized dogs.
The direct negative inotropic actions of calcium channel blockers limit the use of these otherwise effective systemic and coronary vasodilators in patients with heart failure. We studied the effects of amrinone pretreatment on the dose--hemodynamic response curve of diltiazem in order to test the hypothesis that amrinone might potentiate diltiazem's positive effects in anesthetized dogs. ⋯ We propose that amrinone, by inhibiting phosphodiesterase, potentiates diltiazem vasodilation and reflexly secreted catecholamines' actions on the heart. This positive interaction may permit effective use of lower doses of diltiazem, thus circumventing its dose-limiting direct negative effects while still profitting from beneficial peripheral, reflex, and coronary actions.