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Cadmium-induced arteriolar constriction in skeletal muscle microcirculation
C Zhang1, G S Thind, I G Joshua
1Department of Pharmacology and Toxicology, University of Louisville, Kentucky 40292.
American Journal of Hypertension
|April 1, 1993
Summary
Cadmium exposure constricts large arterioles in skeletal muscle, contributing to hypertension. This effect is calcium-dependent and not mediated by alpha-adrenergic receptors, highlighting a novel vascular mechanism.
Area of Science:
- Environmental toxicology
- Cardiovascular physiology
- Vascular biology
Background:
- Cadmium is an environmental pollutant linked to hypertension.
- Hypertension is associated with increased peripheral vascular resistance.
- Previous studies focused on large arteries, not resistance arterioles.
Purpose of the Study:
- To investigate cadmium's direct effects on resistance arterioles in skeletal muscle.
- To elucidate the mechanisms underlying cadmium-induced vascular changes.
Main Methods:
- Used the intact rat cremaster muscle preparation.
- Assessed cadmium's action on arterioles of varying sizes (15-120 microns).
- Investigated the role of alpha-adrenergic receptors and extracellular calcium levels.
Main Results:
- Cadmium caused concentration-dependent constriction of large arterioles (50-120 microns).
- Smaller arterioles (15-30 microns) showed no change in diameter.
- Constriction was not blocked by alpha-adrenergic receptor blockade.
- Low extracellular calcium attenuated cadmium-induced constriction, while repletion enhanced it.
Conclusions:
- Cadmium directly constricts resistance arterioles in skeletal muscle.
- This constriction is selective for larger arterioles and calcium-dependent.
- Cadmium's hypertensive effects may involve skeletal muscle arteriolar constriction.