To determine if treatment with antibiotics altered metabolism of cocaine, levels of benzoylecygonine, the primary metabolite of cocaine, were measured in serum of acutely treated animals. For these experiments Control or Antibiotic-treated animals were given a single injection of 20 or 5 mg/kg cocaine. Animals were killed by rapid decapitation at 30, 60, or 120 minutes after the injection of cocaine. Trunk blood was allowed to sit at room temperature for at least one hour to allow for full clotting. Samples were then spun at 1,200 × g for 15 minutes and the supernatant was saved as serum. Serum concentration of benzoylecygonine was measured using a direct benzoylecygonine ELISA (Sigma-Aldrich) according to manufacturers instructions.
