Cytophotometric analyses of brain neuronal RNA in soman intoxicated rabbits.

Quantitative azure B-RNA cytophotometry was used to monitor metabolic responses of individual neurons of the motor cortex (layer V) and caudate nucleus of soman (pinacolyl methylphosphonofluoridate) poisoned rabbits. Time- and dose-dependent RNA responses were related to the extent of acetylcholinesterase (AChE) inactivation of these 2 brain regions and to overt behavioral manifestations of toxication. A complex pattern of RNA responses was evidenced, with RNA depletion occurring at both arousal and convulsive doses of soman. In general, RNA changes paralleled previously reported metabolic responses observed in soman toxicated rats and mice: (1) linear dose-dependent suppression of RNA was evidenced during the depressant phase but not in the acute excitatory phase of toxication; and (2) RNA depletion was more severe following than during the appearance of excitatory symptoms. These data indicate that soman poisoning results in metabolic correlates of impaired rather than excessive CNS activation. It is postulated that metabolic disturbances are related to blockade of central cholinergic excitation, and that disruption of functionally integrated synaptic activity forms a critically important aspect of toxication.