Influence of dosage, consciousness, and nifedipine on the acute pressor response to intraperitoneally administered cadmium. [Rats]

Journal Article · Sat May 01 04:00:00 EDT 1982 · J. Toxicol. Environ. Health; (United States)

DOI:https://doi.org/10.1080/15287398209530217· OSTI ID:5018712

Hall, C E; Hungerford, S

The acute pressor effect of intraperitoneally administered cadmium was explored over the dose range 0.015-2 mg/kg in both pentobarbital-anesthetized and conscious rats. The former first respondent at 0.031 mg/kg, and successive doublings of that dosage increased the highest pressures attained in a stepwise fashion until a dosage of 0.25 mg/kg, the maximally effective quantity, was reached. Arterial pressure did not rise in conscious rats until a dose of 1 mg/kg, which gave the maximum response within the range examined. Heart-rate changes with Cd were slight, and rarely significant at a given dosage, but pentobarbital invariably caused tachycardia. Anesthetized rats thus gave a graded response, while conscious animals reacted in an all-or-none fashion. The increased pressor responsiveness of rats under pentobarbital can not be ascribed to its cardiac parasympatholytic effects, since sensitivity was not conferred upon conscious rats when pretreated with atropine at a dose producing even greater tachycardia than that caused by pentobarbital. Nifedipine, which blocks calcium entry into smooth muscle cells, prevented the pressor response to cadmium when given as pretreatment and terminated an ongoing response when give intercurrently. Possible mechanisms to account for the observed behavior are considered.

• Research Organization: Univ. of Texas Medical Branch, Galveston
• OSTI ID: 5018712
• Journal Information: J. Toxicol. Environ. Health; (United States), Journal Name: J. Toxicol. Environ. Health; (United States) Journal Issue: 5-6 Vol. 9:5-6; ISSN JTEHD
• Country of Publication: United States
• Language: English

Related Subjects

560305* -- Chemicals Metabolism & Toxicology-- Vertebrates-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BIOLOGICAL EFFECTS
BLOOD PRESSURE
CADMIUM
DOSE-RESPONSE RELATIONSHIPS
ELEMENTS
INJECTION
INTAKE
INTRAPERITONEAL INJECTION
MAMMALS
METALS
RATS
RESPONSE MODIFYING FACTORS
RODENTS
VARIATIONS
VASODILATION
VERTEBRATES