Recovery of synaptic transmission from oxygen glucose deprivation in Syrian hamster hippocampi is temperature dependent and enhanced in hibernation (877.11)

Abstract

It is not known if recovery of signal processing following transient oxygen glucose deprivation (OGD) is greater in hippocampal slices from hibernating hamsters (HH) than in slices from nonhibernating euthermic hamsters (EU). We hypothesized that HH slices recover synaptic transmission more completely than do EU slices, and that decreased temperature further enhances recovery. To test these two hypotheses, evoked response amplitudes (ERAs) of CA1 neurons to afferent stimulation were measured during a 15 min control period [slices perfused with oxygenated artificial cerebrospinal fluid (O2 aCSF, 10 mM glucose)], followed by OGD treatment (perfusate switched to aCSF gassed with nitrogen and no glucose) for 10 min, and a 30 min recovery period (slices returned to O2 aCSF, 10 mM glucose). At 35°C, 10 min after OGD treatment, HH ERAs had recovered to 65.7 ± 12.6% (n=9) of control while EU ERAs had recovered to 22.9 ± 8.0% (n=17; P<0.05). Lower slice temperatures (25°C and 30°C) were neuroprotective for both HH and EU, while the hibernating state afforded no additional neuroprotection. These data support our hypotheses that HH slices are more tolerant to OGD than are EH slices, that decreased temperatures further enhance protection in both HH and EH slices, and suggest that preparation for hibernation induces neuroprotective mechanisms in this facultative hibernator.Grant Funding Source: Supported by UC Davis Provost's Undergraduate Fellowship to AM