Cardiac sensitization induced by phenobarbitone and prolonged by CS2.

Area of Science:

• Pharmacology
• Toxicology
• Cardiovascular Physiology

Background:

• Phenobarbitone pretreatment alters rat cardiac response.
• Starvation affects metabolic and physiological states.

Purpose of the Study:

• To investigate the combined effects of phenobarbitone, starvation, and carbon disulfide (CS2) on noradrenaline-induced arrhythmogenic effects in male rats.
• To determine if CS2 exposure can modulate these altered cardiac responses.

Main Methods:

• Male rats were pretreated with phenobarbitone (80 mg/kg, then 50 mg/kg) and starved.
• Noradrenaline (8 µg/kg, i.v.) was administered to assess arrhythmogenic effects.
• Rats were exposed to 4.0 mg/l CS2 daily for 4 hours, starting 24 hours after phenobarbitone administration.

Main Results:

• Phenobarbitone and starvation significantly increased the arrhythmogenic effect of noradrenaline.
• Daily CS2 exposure prevented the normal decline in susceptibility to noradrenaline on days 3 and 4 post-phenobarbitone.
• Unexposed rats showed a return to normal noradrenaline responsiveness.

Conclusions:

• Combined phenobarbitone and starvation enhance noradrenaline-induced cardiac arrhythmias in rats.
• Carbon disulfide exposure mitigates the altered cardiac susceptibility induced by phenobarbitone and starvation.
• This suggests a complex interaction between sedative-hypnotics, nutritional status, and toxicant exposure on cardiovascular regulation.