title: Cardiovascular toxicity and tissue proton T1 response to manganese injection in the dog and rabbit.
abstract: Paramagnetic substances that shorten proton T1 relaxation time have promise as nuclear magnetic resonance (NMR) contrast agents. The cardiovascular toxicity and tissue T1 response to 0.01-0.1 mM/kg intravenous doses of MnCl2 in rabbits and dogs were studied. There were dose-dependent changes in cardiac electrophysiology and arterial blood pressure consistent with the calcium-blocking properties of manganous ion. There were also dose-dependent and organ-specific changes in tissue proton T1. The sensitivity of organ T1 was expressed as the dose of manganese required to shorten the normal T1 by 50%. Liver, kidney, and heart were most sensitive, while skeletal muscle and adipose tissue were insensitive. MnCl2 is an effective NMR contrast agent, but its toxicity may be excessive for clinical use.
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002712:Chlorides; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D017895:Manganese Compounds; D020149:Manganese Poisoning; D009200:Myocardial Contraction / Q000187:drug effects*; D011522:Protons; D011817:Rabbits
chemical_list: D002712:Chlorides; D017895:Manganese Compounds; D011522:Protons; C025340:manganese chloride