title: Learning impairment caused by intra-CA1 microinjection of testosterone increases the number of astrocytes.
abstract: The hippocampus is essentially involved in learning and memory, and is known to be a target for androgen actions. As neuron-astrocyte interactions play a crucial role during development and in the adult brain, it is thought that astrocytes support learning and memory through specific mechanisms. In this study, the effect of testosterone-induced impairment of acquisition and retrieval of long-term memory, on the number of astrocytes was studied. Adult male albino Wistar rats were bilaterally cannulated into the CA1 region and received 80 microg/0.5 microl of testosterone enanthate dissolved in DMSO as vehicle. In trained groups injection was done 30 min before training. Our results showed that pre-training administration of testosterone increased escape latency and the traveled distance, as compared to intact or DMSO administered (sham-operated) counterparts. Testosterone administration also increased the number of astrocytes in rats, compared to sham-operated and intact animals in both trained and non-trained groups. We have also found that spatial learning could increase the number of astrocytes in the hippocampus as a center of long-term learning and memory and recall. It is concluded that, testosterone-induced impairment in learning and memory, causes an increase in the number of astrocytes in the CA1 region of rat hippocampus.
authors.affiliation: Department of Physiology, School of Biology, College of Science, University of Tehran, Tehran, Iran.
authors.forename: Shahla
authors.initials: S
authors.lastname: Emamian
authors.forename: Nasser
authors.initials: N
authors.lastname: Naghdi
authors.forename: Houri
authors.initials: H
authors.lastname: Sepehri
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Jahanshahi
authors.forename: Yousef
authors.initials: Y
authors.lastname: Sadeghi
authors.forename: Samira
authors.initials: S
authors.lastname: Choopani
mesh_terms: D000704:Analysis of Variance; D000728:Androgens / Q000494:pharmacology*; D000818:Animals; D001253:Astrocytes / Q000473:pathology*; D001522:Behavior, Animal; D002452:Cell Count / Q000379:methods; D006624:Hippocampus / Q000187:drug effects* / Q000473:pathology; D007859:Learning Disabilities / Q000139:chemically induced* / Q000473:pathology*; D008297:Male; D018782:Maze Learning / Q000187:drug effects; D008845:Microinjections / Q000379:methods; D009474:Neurons / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000187:drug effects; D013739:Testosterone / Q000494:pharmacology*
chemical_list: D000728:Androgens; D013739:Testosterone