Comparison of glutamic acid decarboxylase 67 immunoreactive neurons in the hippocampal CA1 region at various age stages in dogs.
The hippocampus is a main brain region concerning learning and memory processes. It is imperative to determine the extent of alterations in number and function of inhibitory GABAergic interneurons in the hippocampus as a function of age. We examined changes in GABAergic neurons in the hippocampal CA1 region at various ages of dogs using glutamic acid decarboxylase 67 (GAD67), which is a rate-limiting enzyme for GABA synthesis. We found only one band in the brain homogenates in dogs as well as mice and rats. GAD67 immunoreactive neurons in 1-year-old dogs were mainly detected in the stratum oriens. In the 6-year-old group, GAD67 immunoreactive neurons were evenly distributed in the CA1 region, and numbers of the neurons were highest among all experimental groups. Thereafter, GAD67 immunoreactive neurons were significantly decreased region with age: GAD67 immunoreactive neurons were scarcely found in the CA1 region in 10-year-old dogs. The reduction of GAD67 immunoreactive neurons in the hippocampal CA1 region may be closely related to highly susceptibility to memory loss in old aged dogs.
Hwang
In Koo
IK
Department of Anatomy and Cell Biology, College of Veterinary Medicine and BK21 Program for Veterinary Science, Seoul National University, Seoul 151-742, South Korea.
Li
Hua
H
Yoo
Ki-Yeon
KY
Choi
Jung Hoon
JH
Lee
Choong Hyun
CH
Chung
Dae Won
DW
Kim
Dae Won
DW
Seong
Je Kyung
JK
Yoon
Yeo Sung
YS
Lee
In Se
IS
Won
Moo-Ho
MH
D000375:Aging; D000818:Animals; D004285:Dogs; D005968:Glutamate Decarboxylase / Q000378:metabolism*; D006624:Hippocampus / Q000166:cytology*; D051379:Mice; D009474:Neurons / Q000201:enzymology*; D051381:Rats
D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1