Cardiac arrest in rodents: Maximal duration compatible with a recovery of neuronal activity

Abstract

We report here that during a permanent cardiac arrest, rodent brain tissue is ''physiologically'' preserved in situ in a particular quiescent state. This state is characterized by the absence of electrical activity and by a critical period of 5-6 hr during which brain tissue can be reactivated upon restoration of a simple energy (glucose͞oxygen) supply. In rat brain slices prepared 1-6 hr after cardiac arrest and maintained in vitro for several hours, cells with normal morphological features, intrinsic membrane properties, and spontaneous synaptic activity were recorded from various brain regions. In addition to functional membrane channels, these neurons expressed mRNA, as revealed by single-cell reverse transcription-PCR, and could synthesize proteins de novo. Slices prepared after longer delays did not recover. In a guinea pig isolated whole-brain preparation that was cannulated and perfused with oxygenated saline 1-2 hr after cardiac arrest, cell activity and functional long-range synaptic connections could be restored although the electroencephalogram remained isoelectric. Perfusion of the isolated brain with the ␥-aminobutyric acid A receptor antagonist picrotoxin, however, could induce self-sustained temporal lobe epilepsy. Thus, in rodents, the duration of cardiac arrest compatible with a short-term recovery of neuronal activity is much longer than previously expected. The analysis of the parameters that regulate this duration may bring new insights into the prevention of postischemic damages.Cardiac arrest lasting a few seconds to a couple of minutes can be reversed without brain damage upon cardiopulmonary resuscitation. After cardiac arrests lasting longer, however, reperfusion of the brain is accompanied by delayed irreversible brain damage that occurs several days after reperfusion of the tissue (for reviews, see refs. 1 and 2). The postischemic period during which neuronal activity recovers but which precedes the appearance of delayed damage is particularly important because it constitutes a therapeutic window in which to prevent delayed cell death. In animal models of global normothermic ischemia, it has been shown that this postischemic period occurs even after a complete interruption of cerebral blood flow lasting up to 1 hr (3-6). Our purpose here was to evaluate the maximal duration of cardiac arrest compatible with the occurrence of this postischemic period. The early phase of the period was analyzed in acute brain tissue prepared after a cardiac arrest of several hours and maintained in vitro.Criteria characterizing acute tissue health in vitro are not clearly established (7). However, the association of normal electrophysiological and morphological parameters with the presence of undegraded mRNAs and the ability of the in vitro tissue to synthesize proteins should constitute an ensemble of signs representative of good health. Furthermore, the evolution of these parameters as a function of the delay between cardiac arrest and brain tissue reoxygenation should reflect the ability of t...

Temperature and time interval for culture of postmortem neurons from adult rat cortex

“…The fast inward currents are consistent with fast voltage‐activated sodium channels. Our findings are supported by the work of Charpak and Audinat (1998) in which slice preparations exhibited normal neuronal characteristics, such as resting membrane potential, field potential, firing properties, and morphology for up to 5 hr postmortem. Evans et al (1998) as well as data presented here have shown that neurons in culture from 0 and 24 hr postmortem cultures posses normal neuronal characteristics.…”

Restoration of brain circulation and cellular functions hours post-mortem

“…Previous studies have reported in cranio perfusion of dog and macaque brains using allogenic whole-blood 48,49 , as well as the isolation 50 and perfusion 14,51,52 of the small rodent (i.e., guinea pig) brain utilizing oxygenated cerebrospinal fluid. However, these earlier studies were conducted under hypothermic conditions on acute brain tissue preparations with negligible PMI, in contrast to the present study.…”

Cells in human postmortem brain tissue slices remain alive for several weeks in culture

“…The agonal state at death was assessed using the pH of the cerebrospinal fluid (16,17). During the postmortem delay, the bodies of the patients were transported to the autopsy room at ambient temperature, which has been shown to be compatible with neuronal survival after cardiac arrest in rodents (15,18).…”