Adult Sprague-Dawley Rats were trained to a competent level in the 24 odor span test. The trained rats were dosed with either saline or CPP for subsequent trials. CPP was dissolved in 0.9% saline and delivered as 1 mL intraperitoneal injections having corresponding doses of 3, 10, and 17 mg/kg. In follow up sessions rat were dosed with 10 and 17 mg/kg of CPP along with 0.75 mg/kg of nicotine. Working memory was impaired by CPP in a dose dependent manner, although long term reference memory was recoverable. Nicotine did not ameliorate CPP-induced impairments in memory span or accuracy, but it did reduce the impairment of longest run time relative to 10 mg/kg CPP.

Microelectrophoretic studies were conducted on extracted rat neurons. Cells were incubated with 25mM CPP in 175 mm NaCl or 5mM CPP in 200mM NaCl. The firing rate of each neuron was recorded in response to cyclical ejection of the agonist. CPP was able to rapidly reduced excitations due to NMDA by ~ 80%. As a follow-up experiment in the same study, cortical wedges were taken from rat cingulate cortex and placed in a two compartment chamber with artificial cerebrospinal fluid. Depolarization of neurons in response to bath application of amino acids was recorded as a d.c. potential change across a grease seal barrier placed near the junction between grey and white matter. A dose response relationship was recorded by applying various concentrations of CPP. CPP was found to have an IC50 of 0.64 microM versus 40 microM cortical wedges.