Age-dependent changes in brain glycine concentration and strychnine-induced seizures in the rat

• Published in: Brain research Vol. 482; no. 2; p. 247
• Main Authors: Hunter, C, Chung, E, Van Woert, M H
• Format: Journal Article
• Language: English
• Published: Netherlands 20-03-1989
• Subjects: Aging - metabolism; Aging - physiology; Animals; Glycine - metabolism; Medulla Oblongata - growth & development; Medulla Oblongata - metabolism; Medulla Oblongata - physiopathology; Rats; Rats, Inbred F344; Seizures - chemically induced; Seizures - metabolism; Seizures - physiopathology; Spinal Cord - growth & development; Spinal Cord - metabolism; Spinal Cord - physiopathology; Strychnine - metabolism; Strychnine - pharmacology
• ISSN: 0006-8993
• DOI: 10.1016/0006-8993(89)91187-6

Glycine levels and receptor binding were measured in the medulla and spinal cord of 2-month, 10-month, and 24-month-old Fischer 344 rats. The behavioral response to the administration of the glycine antagonist, strychnine, was also evaluated in 2- and 24-month-old animals to investigate the relevance of these parameters to the susceptibility to seizures. Significant reductions in glycine in both the spinal cord and medulla occurred from 2 to 24 months of age. The glycine precursors, serine and threonine, were decreased only in the spinal cord. [3H]Strychnine binding was also decreased by 38% and 34% in the medulla and spinal cord, respectively, of 24-month-old rats compared to 2-month-olds. [3H]GABA binding was similarly reduced while no age-related changes in [3H]diazepam binding in the spinal cord were detected. Comparison of 2- and 24-month-old animals after systemic injection of 1.75 mg/kg strychnine showed that senescent animals have a higher incidence of seizures and mortality compared to young animals. Decreases in glycinergic neurotransmission may lower strychnine seizure threshold in the aged animal.