Faculty Collaboration Database

Stereological quantification of GAD-67-immunoreactive neurons and boutons in the hippocampus of middle-aged and old Fischer 344 x Brown Norway rats. J Comp Neurol 2004 Oct 18;478(3):282-91

Date

09/16/2004

Pubmed ID

15368530

DOI

10.1002/cne.20303

Scopus ID

2-s2.0-4744350870 (requires institutional sign-in at Scopus site)   51 Citations

Abstract

The aging process in rodents is associated with learning and memory impairments that are correlated with changes in multiple neurotransmitter systems in the hippocampus. For example, the gamma-aminobutyric acid (GABA)ergic system is compromised in old compared with young rats (Shetty and Turner [1998] J. Comp. Neurol. 394:252-269; Vela et al. [2003] J. Neurochem. 85:368-377; Potier et al. [1992] Neuroscience 48:793-806; Potier et al. [1994] Brain Res. 661:181-188). The present study investigated the important issue of whether there is a decline of the GABAergic inhibitory system between middle and old age. Five middle-aged (15-17 months) and five old (25-29 months) Fischer 344 x Brown Norway male rats were perfused, and coronal sections through the dorsal hippocampus were immunoreacted with antibodies either to NeuN, a neuronal marker, or to the 67-kDa isoform of glutamic acid decarboxylase (GAD), the rate-limiting enzyme for GABA synthesis. Using the optical dissector technique, NeuN-immunoreactive (IR) cells, GAD-IR cells, and GAD-IR boutons were quantified stereologically in the dentate gyrus, CA3, and CA1. The resulting GAD-IR cell and GAD-IR bouton densities then were normalized to NeuN-IR cell density to exclude the possible confound of tissue shrinkage. The results revealed a significant decline in GAD-IR cells between middle and old age in CA1 but not in dentate gyrus or CA3. Interestingly, GAD-IR boutons did not show a decline in CA1, CA3, or dentate gyrus between middle and old age. It is possible that loss of CA1 inhibitory interneurons in the dorsal hippocampus contributes to the learning and memory impairments reported in old rats.

Author List

Shi L, Argenta AE, Winseck AK, Brunso-Bechtold JK

MESH terms used to index this publication - Major topics in bold

Age Factors
Animals
Cell Count
Glutamate Decarboxylase
Hippocampus
Immunohistochemistry
Isoenzymes
Male
Neurons
Nuclear Proteins
Presynaptic Terminals
Rats
Rats, Inbred F344
Stereotaxic Techniques