The effect of Ginkgo biloba extract on scopolamine-induced apoptosis in the hippocampus of rats

Apoptosis, known as programmed cell death, plays a crucial role in normal development and tissue homeostasis. Apoptosis is also involved in neurodegenerative diseases such as Alzheimer's disease. Amnesia refers to the loss of memory and can also be a warning sign of neurodegenerative diseases. The antioxidant properties of Ginkgo biloba extract was known previously. Therefore, the aim of this study was to examine the effects of Ginkgo biloba extract on the rat's hippocampal apoptotic neurons number after Scopolamine based amnesia. Thirty-six adult male Wistar rats were used. Rats were randomly divided into control, sham, protective and treatment groups. The rats in the sham group received only scopolamine hydrobromide (3 mg/kg) intraperitoneally. The rats in the protective and treatment groups received Ginkgo biloba extract (40, 80 mg/kg) for 7 days intraperitoneally before/after scopolamine injection. Then 48 h after the last injection, the brains of rats were withdrawn and fixed with paraformaldehyde, and then, after histological processing, the slices were stained with the TUNEL kit for apoptotic neurons. Data were compared by the ANOVA Post Hoc Tukey test; P < 0.05 was considered significant. Our results showed that Scopolamine (in the sham group) increased significantly the number of apoptotic neurons in all areas of the hippocampus compared with the control. Whereas, Ginkgo biloba extract reduce the neuronal apoptosis in the hippocampus before and/or after encounter with scopolamine. We concluded that pretreatment and treatment injection of Ginkgo biloba extract can have a protective effect for neurons and it can limit apoptosis in all area of the hippocampus. © 2013 Japanese Association of Anatomists

Scopolamine reduces the density of M1 muscarinic neurons in rats' hippocampus

Cholinergic system in CNS is involved in learning and memory. Scopolamine as muscarinic acetylcholine receptor antagonist is used for creation of memory impairment. The purpose of this study is evaluation of scopolamine-based amnesia on memory retention and the effect of this phenomenon on the number of neurons contains M1-receptors in the male Wistar rats hippocampal regions. Thirty-five male Wistar rats (200±20 g) were distributed randomly into five groups. Control group (intact samples) and 3 experimental groups with sham group (saline) were tested by the method of passive avoidance (shuttle box) in doses of 0.2, 0.5 and 1 mg/kg (intraperitoneally) as a single dose. After one week, memory test was taken from the rats. Finally, brains dissected from sacrificed rats, and then processed tissues were stained with antibody against M1 receptors (Immunohistochemistry technique) followed by counting of hippocampal CA1, CA3 and DG regions. Our results showed significant decrease in neurons contains M1-receptors in all area of hippocampus. We found that the less number of M1-neurons showed in 1 mg/kg dose of scopolamine. We concluded that scopolamine as muscarinic acetylcholine receptor antagonist can reduce dose-dependently the density of M1-neurons in all areas of hippocampus