Nobiletin improves emotional and novelty recognition memory but not spatial referential memory.
How to maintain and enhance cognitive functions for both aged and young populations is a highly interesting subject. But candidate memory-enhancing reagents are tested almost exclusively on lesioned or aged animals. Also, there is insufficient information on the type of memory these reagents can improve. Working memory, located in the prefrontal cortex, manages short-term sensory information, but, by gaining significant relevance, this information is converted to long-term memory by hippocampal formation and/or amygdala, followed by tagging with space-time or emotional cues, respectively. Nobiletin is a product of citrus peel known for cognitive-enhancing effects in various pharmacological and neurodegenerative disease models, yet, it is not well studied in non-lesioned animals and the type of memory that nobiletin can improve remains unclear. In this study, 8-week-old male mice were tested using behavioral measurements for working, spatial referential, emotional and visual recognition memory after daily administration of nobiletin. While nobiletin did not induce any change of spontaneous activity in the open field test, freezing by fear conditioning and novel object recognition increased. However, the effectiveness of spatial navigation in the Y-maze and Morris water maze was not improved. These results mean that nobiletin can specifically improve memories of emotionally salient information associated with fear and novelty, but not of spatial information without emotional saliency. Accordingly, the use of nobiletin on normal subjects as a memory enhancer would be more effective on emotional types but may have limited value for the improvement of episodic memories.
Graduate School of East-West Medical Science, Kyung Hee University, #1732 Deogyeong-daero, Giheung-gu, Yongin, 446-701, Republic of Korea.
Jiyun
J
Kang
Graduate School of East-West Medical Science, Kyung Hee University, #1732 Deogyeong-daero, Giheung-gu, Yongin, 446-701, Republic of Korea.
Jung-Won
JW
Shin
Graduate School of East-West Medical Science, Kyung Hee University, #1732 Deogyeong-daero, Giheung-gu, Yongin, 446-701, Republic of Korea.
Yoo-Rim
YR
Kim
Graduate School of East-West Medical Science, Kyung Hee University, #1732 Deogyeong-daero, Giheung-gu, Yongin, 446-701, Republic of Korea.
Kelley M
KM
Swanberg
Department of Clinical Korean Medicine Graduate School, Kyung Hee University, Seoul, Republic of Korea.
Yooseung
Y
Kim
Graduate School of East-West Medical Science, Kyung Hee University, #1732 Deogyeong-daero, Giheung-gu, Yongin, 446-701, Republic of Korea.
Jae Ryong
JR
Bae
Graduate School of East-West Medical Science, Kyung Hee University, #1732 Deogyeong-daero, Giheung-gu, Yongin, 446-701, Republic of Korea.
Young Ki
YK
Kim
Graduate School of East-West Medical Science, Kyung Hee University, #1732 Deogyeong-daero, Giheung-gu, Yongin, 446-701, Republic of Korea.
Jinwon
J
Lee
Graduate School of East-West Medical Science, Kyung Hee University, #1732 Deogyeong-daero, Giheung-gu, Yongin, 446-701, Republic of Korea.
Soo-Yeon
SY
Kim
Graduate School of East-West Medical Science, Kyung Hee University, #1732 Deogyeong-daero, Giheung-gu, Yongin, 446-701, Republic of Korea.
Nak-Won
NW
Sohn
Graduate School of East-West Medical Science, Kyung Hee University, #1732 Deogyeong-daero, Giheung-gu, Yongin, 446-701, Republic of Korea. jethrot@hotmail.com.|East-West Medical Research Institute, Kyung Hee University, Seoul, Republic of Korea. jethrot@hotmail.com.
Sungho
http://orcid.org/0000-0002-9347-7902
S
Maeng
D000818:Animals; D004644:Emotions; D047309:Flavones / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008569:Memory Disorders / Q000188:drug therapy*; D008570:Memory, Short-Term / Q000187:drug effects*; D051379:Mice
D047309:Flavones; C008661:nobiletin
Contextual memory; Donepezil; Emotional memory; Nobiletin; Visual recognition memory; Working memory