I. V. self-administration of cinepazide by rats and the preference of the animals for this drug were studied; and the following were found: 1. I. V. self-administration of cinepazide to rats at dosages of 4, 15, 30, and 60 mg/kg/injection for 7 consecutive days resulted in no self-administration by the animals of the drug far beyond the operant level. 2. Rats undertook the self-administration of cocaine at 1 mg/kg/injection continuously, unlike that of saline or cinepazide. 3. Cross application of cinepazide at dosages of 4, 15, 30 and 60 mg/kg/injection to rats on i. v. self-administration of cocaine failed to substitute itself for the latter. These findings suggested that cinepazide was not a positive reinforcer. 4. Rats exhibited preference for morphine, codeine and pethidine but not for cinepazide. 5. The rats exhibiting preference for morphine also exhibited preference for codeine and pethidine in cross choice trials with these drugs but not for cinepazide in the cross choice trial with this drug. The findings in 4 and 5 suggested that rats showed no preference for cinepazide and that cinepazide failed to maintain the rats' preference for morphine.
