Olfactory bulbectomy protects hippocampal pyramidal neurons against excitotoxic death.
The olfactory system is functionally linked to the hippocampus, and odors can modify the activity of hippocampal neurons. Because hippocampal neurons are selectively vulnerable to death in several prominent neurodegenerative conditions, we tested the hypothesis that activity in olfactory pathways can modify the sensitivity of hippocampal neurons to excitotoxic damage. We report that rats subjected to olfactory bulbectomy exhibit a decrease in the vulnerability of hippocampal pyramidal neurons to excitotoxic injury. Four-month-old male Sprague-Dawley rats were subjected to bilateral olfactory bulbectomy or a sham operation. Three months later the rats were given a unilateral infusion of kainic acid in the dorsal hippocampus and were euthanized 24 h later. There was a threefold increase in the number of CA3 neurons that survived kainic acid administration in the bulbectomized rats compared to sham-operated rats. These findings provide the first evidence that olfactory input affects the vulnerability of neurons to excitotoxic death.
Gary
Devin S
DS
Laboratory of Neurosciences, National Institute on Aging Gerontology Research Center, 5600 Nathan Shock Drive, Baltimore, Maryland 21224, USA.
Getchell
Thomas V
TV
Getchell
Marilyn L
ML
Mattson
Mark P
MP
D000818:Animals; D002452:Cell Count; D002470:Cell Survival / Q000187:drug effects; D004351:Drug Resistance / Q000502:physiology; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D007608:Kainic Acid / Q000494:pharmacology; D008297:Male; D009498:Neurotoxins / Q000494:pharmacology*; D009830:Olfactory Bulb / Q000502:physiology* / Q000601:surgery; D017966:Pyramidal Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D009498:Neurotoxins; D007608:Kainic Acid