Leptin is well known to be involved in the inhibition of feeding, hermogenesis, reproduction, and neuroendocrine functions through its actions on the rodent's hypothalamic receptors. Leptin facilitated the presynaptic transmitter release and postsynaptic sensitivity to the transmitters in the hippocampal CA1 neurons. Thus, long-term potentiation (LTP) and the phosphorylation of Ca2+/calmodulin protein kinase II (CaMK II) were facilitated in the CA1 neurons. Therefore behavioral performance related to spatial learning and memory was improved by leptin in vivo applications. Orexin-A produced by glucose-sensitive neurons in the lateral hypothalamic area (LHA) and released during food intake facilitates feeding. Orexin-A suppressed LTP and CaMK II phosphorylation without affecting the presynaptic transmitter release. Therefore behavioral performance on learning and memory was impaired. The present studies suggest that leptin and orexin signalings in the brain may have important implications for cognitive function.
- Ca/calmodulin protein kinase II
- cognitive function
- learning and memory
ASJC Scopus subject areas