Effects of streptomycin and neomycin on the adrenal medulla of dogs.
The blocking effects of streptomycin and neomycin upon adrenal neurotransmission were studied in dogs. The pressor responses to splanchnic nerve stimulation (SNS) or 50 micrograms/kg nicotine were both blocked by 100 mg/kg but not by 50 mg/kg of the antibiotics injected systemically through the femoral vein. The effect was reversed by intravenous infusion of calcium chloride. The pressor response to SNS, but not that to nicotine, was blocked by the antibiotics injected into the adrenal gland through the adrenolumbar vein at doses up to 10 mg/kg. This effect was reversed by 50 micrograms/kg calcium chloride. Higher doses of antibiotics blocked the response to both stimuli, with only the response to nicotine being reversed by calcium chloride. These data indicate that streptomycin and neomycin block adrenal neurotransmission by interfering with calcium ions at pre- or pre-plus postsynaptic levels depending on the dose and route of administration.
D000313:Adrenal Medulla / Q000187:drug effects*; D000818:Animals; D002122:Calcium Chloride / Q000494:pharmacology; D004285:Dogs; D004347:Drug Interactions; D005260:Female; D007275:Injections, Intravenous; D008297:Male; D009355:Neomycin / Q000008:administration & dosage / Q000494:pharmacology*; D013307:Streptomycin / Q000008:administration & dosage / Q000494:pharmacology*; D009435:Synaptic Transmission / Q000187:drug effects*
D009355:Neomycin; D002122:Calcium Chloride; D013307:Streptomycin