Immunoreactivities and levels of mineralocorticoid and glucocorticoid receptors in the hippocampal CA1 region and dentate gyrus of adult and aged dogs.
Corticosteroids are important factors in the maintenance of homeostasis in the brain. They are regulated via the interaction with two corticosteroid receptor systems-the mineralocorticoid (MR) and glucocorticoid receptor (GR). In the present study, we observed age-related changes in serum cortisol levels, and immunoreactivities and protein levels of MR and GR in the hippocampal CA1 region and dentate gyrus. The serum cortisol levels were significantly high (about twofold) in the aged group compared to that in the adult group. In the adult dog (2-3 years old), MR and GR immunoreactivity was detected in neurons in the pyramidal layer of the CA1 region, and in the granular and multiform layers of the dentate gyrus. In the aged dog (10-12 years old), MR immunoreactivity in the CA1 region was significantly decreased, especially, in the dentate multiform layer. In contrast, GR immunoreactivity in the aged dog was slightly decreased in the CA1 region and dentate gyrus. In the Western blot analysis, MR protein level in the aged dog was significantly lower compared to that of the adult dog; GR protein level in the aged dog was not significantly decreased. This result indicates that the reduction of MR immunoreactivity and protein level in the hippocampus of the aged dog may be associated with neural dysfunction in the aged hippocampus.
Choi
Jung Hoon
JH
Department of Anatomy and Cell Biology, College of Veterinary Medicine, Seoul National University, Seoul 151-742, South Korea.
Hwang
In Koo
IK
Lee
Choong Hyun
CH
Chung
Dae Won
DW
Yoo
Ki-Yeon
KY
Li
Hua
H
Won
Moo-Ho
MH
Seong
Je Kyung
JK
Yoon
Yeo Sung
YS
Lee
In Se
IS
D000375:Aging / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D018891:Dentate Gyrus / Q000254:growth & development / Q000378:metabolism*; D004285:Dogs; D006624:Hippocampus / Q000254:growth & development / Q000378:metabolism*; D006854:Hydrocortisone / Q000097:blood / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D011965:Receptors, Glucocorticoid / Q000096:biosynthesis*; D018161:Receptors, Mineralocorticoid / Q000096:biosynthesis*
D011965:Receptors, Glucocorticoid; D018161:Receptors, Mineralocorticoid; D006854:Hydrocortisone