Investigating the effect of ghrelin on improving memory and learning ability in animals: A systematic review

Abstract

Ghrelin does an important role in neurological functions such as memory, learning, and cognition as well. There is some evidence that ghrelin can improve memory. This study aimed to evaluate the effects of ghrelin on rat memory. A systematic search was conducted to identify papers published by Iranian authors in the Web of Science, PubMed, Scopus, Embase, and Google Scholar electronic databases from January 2010 to December 2019 with the PRISMA statement. Totally, 547 animals were listed in our systematic review. All of the animals were male Wistar rats with a mean weight of 250±280 g. The Morris Water Behavior behavioral test and the passive avoidance task were performed to evaluate memory. Truly, injection of ghrelin appears to enhance the compactness of the synapse dendritic spines in the hypothalamus. These findings indicate that ghrelin has a prospective role to recover learning and memory ability in animal models, suggesting it as a candidate therapy for memory.