title: Enhancement of GABA-activated membrane currents in aged Fischer 344 rat basal forebrain neurons.
abstract: Changes in GABAergic systems have been widely documented during development. Similar changes might also occur during aging, but little information is currently available. Whole-cell and single-channel GABAA-activated currents were studied in acutely dissociated basal forebrain neurons. An age-related increase in whole-cell GABA currents was observed in cells from aged (19-25 month) Fischer 344 rats. The GABA current from aged animals displayed a greater maximum response, with no change in EC50 or slope of the GABA response curve. A reduction in use-dependent slow receptor desensitization was also observed in aged cells. Single-channel conductance and channel open time were unchanged with age, suggesting no alteration in the properties of single GABA channels. The benzodiazepine, midazolam, potentiated GABA currents to a greater degree in aged animals, consistent with previous reports of enhanced benzodiazepine activity with age. Ontogeny of the GABAA receptor/ion channel complex may continue through the stages of development, maturation, and aging.
authors.affiliation: Department of Medical Pharmacology and Toxicology, College of Medicine, Texas A&M University, College Station 77843.
authors.forename: W H
authors.initials: WH
authors.lastname: Griffith
authors.forename: D A
authors.initials: DA
authors.lastname: Murchison
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000375:Aging / Q000502:physiology*; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D004357:Drug Synergism; D015640:Ion Channel Gating / Q000187:drug effects; D007811:Lanthanum / Q000494:pharmacology; D008874:Midazolam / Q000494:pharmacology; D010424:Pentobarbital / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D011963:Receptors, GABA-A / Q000187:drug effects* / Q000502:physiology; D012688:Septum Pellucidum / Q000187:drug effects* / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology; D015032:Zinc / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
chemical_list: D011963:Receptors, GABA-A; D013779:Tetrodotoxin; D005680:gamma-Aminobutyric Acid; D007811:Lanthanum; D010424:Pentobarbital; D015032:Zinc; D008874:Midazolam; D001640:Bicuculline