Sex Differences in Long-Term Potentiation at Temporoammonic-CA1 Synapses: Potential Implications for Memory Consolidation.
Sex differences in spatial memory have long been observed in humans, non-human primates and rodents, but the underlying cellular and molecular mechanisms responsible for these differences remain obscure. In the present study we found that adolescent male rats outperformed female rats in 7 d and 28 d retention probes, but not in learning trials and immediate probes, in the Morris water maze task. Male rats also had larger long-term potentiation (LTP) at hippocampal temproammonic-CA1 (TA-CA1) synapses, which have been implicated to play a key role in place field and memory consolidation, when protocols designed to elicit late-stage LTP (LLTP) were used. Interestingly, the ratio of evoked AMPA/NMDA currents was found to be smaller at TA-CA1 synapses in male rats compared to female rats. Protein biotinylation experiments showed that male rats expressed more surface GluN1 receptors in hippocampal CA1 stratum lacunosum-moleculare (SLM) than female rats, although GluA1 expression was also slightly higher in male rats. Taken together, our results suggest that differences in the expression of AMPA and NMDA receptors may affect LTP expression at TA-CA1 synapses in adolescent male and female rats, and thus possibly contribute to the observed sex difference in spatial memory.
Department of Physiology, Southern Illinois University School of Medicine, Carbondale, IL, United States of America.
Xiaoqiang
X
Qi
Department of Physiology, Southern Illinois University School of Medicine, Carbondale, IL, United States of America.
Ke
K
Zhang
The Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, P.R. China.
Ting
T
Xu
Department of Physiology, Southern Illinois University School of Medicine, Carbondale, IL, United States of America.
Vitor Nagai
VN
Yamaki
The Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, P.R. China.
Zhisheng
Z
Wei
The Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, P.R. China.
Mingfa
M
Huang
Department of Anatomy, Southern Illinois University School of Medicine, Carbondale, IL, United States of America.|Neuroscience Research Center, Southern Illinois University School of Medicine, Carbondale, IL, United States of America.
Gregory M
GM
Rose
Department of Physiology, Southern Illinois University School of Medicine, Carbondale, IL, United States of America.|The Institute of Neuroscience, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, P.R. China.|Neuroscience Research Center, Southern Illinois University School of Medicine, Carbondale, IL, United States of America.
Xiang
http://orcid.org/0000-0003-0222-553X
X
Cai
D000818:Animals; D056547:CA1 Region, Hippocampal / Q000502:physiology*; D005260:Female; D017774:Long-Term Potentiation; D008297:Male; D018782:Maze Learning; D000069077:Memory Consolidation / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D012727:Sex Characteristics
D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate