Metalaxyl-induced bradycardia in rats: mediated by alpha-adrenoreceptors.

Abstract

The effect of the fungicide metalaxyl [methyl N-(2-methoxyacetyl)-N-(2,6-xylyl)-DL-alaniate] on cardiac activity was investigated in albino rats anesthetized with phentobarbitone. Metalaxyl caused dose-dependent bradycardia, and at higher doses (250 and 300 mg/kg body weight) the sustained bradycardia led to cardiac arrest. The acetylcholinesterase activities in brain and heart were not affected in metalaxyl-treated rats. However, the bradycardia induced by the fungicide was blocked by pretreatment of rats with the alpha-adrenoreceptor antagonist phentolamine (20 mg/kg, ip). The data suggest that the bradycardia-inducing effect of metalaxyl was not mediated by the cholinergic system but through alpha-adrenoreceptors.

• Authors: K A Naidu, R Radhakrishnamurty
• Journal: Journal of toxicology and environmental health (J Toxicol Environ Health) Vol. 23 Issue 4 Pg. 495-8 ( 1988) ISSN: 0098-4108 [Print] United States
• PMID: 2834560 (Publication Type: Journal Article)

Chemical References

• Fungicides, Industrial
• Receptors, Adrenergic, alpha
• metalaxyl
• Alanine
• Phentolamine

Topics

• Alanine (analogs & derivatives, toxicity)
• Animals
• Bradycardia (chemically induced)
• Female
• Fungicides, Industrial (toxicity)
• Heart Arrest (chemically induced)
• Heart Rate (drug effects)
• Injections, Intraperitoneal
• Male
• Phentolamine (pharmacology)
• Rats
• Rats, Inbred Strains
• Receptors, Adrenergic, alpha (drug effects)