[The influences of neurotransmitters on the traumatic unconsciousness, immediate convulsion and mortality in the experimental mice model].

In order to clearing the influence of neurotransmitters in concussive unconsciousness, immediate convulsion and mortality, the following experiments were performed. Awake male mice of dd-strain were restrained and subjected to head injury using a bakelite weight of 30 gm dropped from a height of 20 cm on to the skull. This injury resulted in immediate loss of consciousness in 100%, convulsive seizure in 66% and death in 30% of animals. The severity of consciousness disturbance was evaluated by two parameters; (1) time interval required for the recovery of righting reflex (RR) and (2) time interval for the recovery of spontaneous movement (SM). Agonist or antagonist of various neurotransmitters was given intraperitoneally 0.5 or 2 hours before injury. The following results were obtained although some of them were statistically not significant. Physostigmine shortened both RR (p less than 0.1) and SM (p less than 0.01), whereas scopolamine did not change these intervals. Atropine sulfate shortened both of them. Nevertheless, atropine methylbromide, which dose not pass through blood-brain-barrier, also had same effects. Methamphetamine shortened both RR (p less than 0.1) and SM (p less than 0.05), whereas haloperidol prolonged these intervals. 5-HTP shortened RR (p less than 0.05), but prolonged SM (p less than 0.1). Methysergide shortened both RR (p less than 0.05) and SM (p less than 0.01). Convulsive seizure was suppressed by physostigmine (p less than 0.01) or 5-HTP (p less than 0.20). These results suggested that suppression of dopaminergic and cholinergic systems, and/or activation of serotonergic system contribute to concussive unconsciousness.