title: Loganin enhances long-term potentiation and recovers scopolamine-induced learning and memory impairments.
abstract: Although the incidence rate of dementia is rapidly growing in the aged population, therapeutic and preventive reagents are still suboptimal. Various model systems are used for the development of such reagents in which scopolamine is one of the favorable pharmacological tools widely applied. Loganin is a major iridoid glycoside obtained from Corni fructus (Cornusofficinalis et Zucc) and demonstrated to have anti-inflammatory, anti-tumor and osteoporosis prevention effects. It has also been found to attenuate Aβ-induced inflammatory reactions and ameliorate memory deficits induced by scopolamine. However, there has been limited information available on how loganin affects learning and memory both electrophysiologically and behaviorally. To assess its effect on learning and memory, we investigated the influence of acute loganin administration on long-term potentiation (LTP) using organotypic cultured hippocampal tissues. In addition, we measured the effects of loganin on the behavior performance related to avoidance memory, short-term spatial navigation memory and long-term spatial learning and memory in the passive avoidance, Y-maze, and Morris water maze learning paradigms, respectively. Loganin dose-dependently increased the total activity of fEPSP after high frequency stimulation and attenuated scopolamine-induced blockade of fEPSP in the hippocampal CA1 area. In accordance with these findings, loganin behaviorally attenuated scopolamine-induced shortening of step-through latency in the passive avoidance test, reduced the percent alternation in the Y-maze, and increased memory retention in the Morris water maze test. These results indicate that loganin can effectively block cholinergic muscarinic receptor blockade -induced deterioration of LTP and memory related behavioral performance. Based on these findings, loganin may aid in the prevention and treatment of Alzheimer's disease and learning and memory-deficit disorders in the future.
authors.affiliation: Department of East-West Medical Science, Graduate School of East-West Medical Science, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Republic of Korea.
authors.forename: Eun-Sang
authors.initials: ES
authors.lastname: Hwang
authors.affiliation: Department of East-West Medical Science, Graduate School of East-West Medical Science, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Republic of Korea.
authors.forename: Hyun-Bum
authors.initials: HB
authors.lastname: Kim
authors.affiliation: Department of East-West Medical Science, Graduate School of East-West Medical Science, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Republic of Korea.
authors.forename: Seok
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of East-West Medicine, Graduate School of East-West Medical Science, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin 446-701, Republic of Korea.
authors.forename: Min-Ji
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Department of Oriental Medicinal Materials and Processing, College of Life Science, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 446-701, Republic of Korea.
authors.forename: Sung-Ok
authors.initials: SO
authors.lastname: Lee
authors.affiliation: Department of Biomedical Engineering, Kyung Hee University, 1 Seocheon-dong, Giheung-gu, Yongin 446-701, Republic of Korea.
authors.forename: Seung-Moo
authors.initials: SM
authors.lastname: Han
authors.affiliation: Department of East-West Medicine, Graduate School of East-West Medical Science, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin 446-701, Republic of Korea. Electronic address: jethrot@khu.ac.kr.
authors.forename: Sungho
authors.initials: S
authors.lastname: Maeng
authors.affiliation: Department of East-West Medicine, Graduate School of East-West Medical Science, Kyung Hee University, Deogyeong-daero, Giheung-gu, Yongin 446-701, Republic of Korea. Electronic address: jihopark@khu.ac.kr.
authors.forename: Ji-Ho
authors.initials: JH
authors.lastname: Park
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D001703:Biophysics; D018680:Cholinergic Antagonists / Q000633:toxicity*; D004558:Electric Stimulation; D006624:Hippocampus / Q000166:cytology; D066298:In Vitro Techniques; D039823:Iridoids / Q000494:pharmacology / Q000627:therapeutic use*; D007859:Learning Disabilities / Q000139:chemically induced / Q000188:drug therapy / Q000473:pathology; D017774:Long-Term Potentiation / Q000187:drug effects*; D018782:Maze Learning / Q000187:drug effects; D008569:Memory Disorders / Q000139:chemically induced / Q000188:drug therapy; D018408:Patch-Clamp Techniques; D051381:Rats; D020127:Recovery of Function / Q000187:drug effects*; D012601:Scopolamine / Q000633:toxicity*
chemical_list: D018680:Cholinergic Antagonists; D039823:Iridoids; D012601:Scopolamine; C059516:loganin