The therapeutic effect of crocin on ketamine-induced retrograde amnesia in rats

Introduction: The glutamatergic system plays an important role in learning and memory. Administration of crocus sativus (Saffron) or its constituent, crocin, facilitates the formation of memory. This research investigated the effect of crocin on antagonizing retrograde amnesia induced by ketamine, a glutamatergic receptor antagonist, in rats by shuttle box.

Methods:  Male Wistar rats were tested to measure their learning behavior in the passive avoidance task. All animals were trained by a 1 mA shock. The drugs were injected immediately after the training was successfully performed. The animals were tested 24h after training to measure Step Through Latency (STL).

Results: On the test day, administration of ketamine (12 mg/kg, ip) impaired the memory after training. Different doses of crocin (2, 5 or  10 mg/kg, ip) were injected 30 min after ketamine, but only 2 mg/kg crocin could improve retrograde amnesia and 5 and 10 mg/kg doses did not have any significant effect on retrograde amnesia. Moreover, administration of crocin (2, 5 or 10 mg/kg, ip) after training had no significant impact on passive avoidance memory by itself.

Conclusion: Considering the therapeutic effect of post-training administration of crocin on ketamine-induced retrograde amnesia, it can be argued that crocin has an interaction with glutamatergic system in formation of passive avoidance memory in rats.