Investigating the Co-administration of Ghrelin and Nicotine Into the Medial Septum and Its Influencing on Morphine Amnestic Effect.

Morphine abuse has been associated with memory disturbance. Ghrelin is a gastrointestinal hormone known as hunger hormone. It also affects cognitive performance via binding ghrelin receptors in central nervous system. On the other hand, the medial septum nicotinic receptors improve memory-associated behavior. Hence, we hypothesized that septal ghrelin receptors could affect the effect of nicotine on morphine-induced memory deficit. We examined this hypothesis in avoidance memory task. We found that subcutaneous administration of morphine inhibited avoidance memory. The effect of morphine was blocked by intra-medial septum injection of nicotine or ghrelin. However, co-infusion of ghrelin with nicotine into the medial septum area had no effect on morphine amnesia. Overall, the study results suggest no interaction between ghrelin and cholinergic nicotinic receptors in morphine amnesia.