Effect of denbufylline in passive avoidance trials in gerbils, following transiet forebrain ischaemia, and in mice

Denbufylline (1,3-di-n-butyl-7-[2-oxopropyl]-xanthine) has been examined in passive avoidance trials in gerbils, following transient forebrain ischaemia, and in mice. Animals were conditioned to avoid a darkened compartment by means of a foot shock received upon entering. Learning and memory were tested 24 hr later by replacing the animals in the box and measuring the latency to enter the dark compartment. In gerbils, transient (5 min) forebrain ischaemia was induced 24 hr prior to training by bilateral closure of the carotid arteries. Controls were sham-ligated. All gerbils received seven subcutaneous injections of saline or denbufylline, the first during forebrain ischaemia or immediately following sham-ligation, and the rest 3, 6, 24, 27, 30, and 48 hr later. Mice received one subcutaneous injection of saline or denbufylline immeediately after training. The results show that denbufylline enhances memory formation in mice after a mild learning stimulus and recollection in gerbils following forebrain ischaemia.