Pj. Syapin et al., EFFECT OF 12 ATMOSPHERES HELIUM-OXYGEN ON THE RESPONSE OF MICE TO CONVULSANT DRUGS, Undersea & hyperbaric medicine, 23(1), 1996, pp. 35-41
Citations number
35
Categorie Soggetti
Medicine Miscellaneus","Marine & Freshwater Biology
The mechanism by which 12 atm abs of a helium-oxygen gas mixture (heli
ox) antagonizes behavioral effects of ethanol is unknown. Although the
threshold for pressure-reversal of general anesthesia and expression
of the high pressure neurologic syndrome (HPNS) is well above 12 atm a
bs in mice, the ethanol antagonism by 12 atm abs heliox could result f
rom similar underlying excitatory effects. To investigate this possibi
lity, the behavior of water-injected control mice and the latency to c
onvulsions in drug-injected mice were determined in 1 atm abs air and
12 atm abs heliox. Four convulsant drugs were tested: picrotoxin (2 mg
/kg), dl-allylglycine (300 mg/kg), isoniazid (300 mg/kg), and l-methio
nine-dl-sulfoximine (170 mg/kg). Responses were videotaped to observe
behavior and to measure latency to the onset of myoclonus and clonus.
Results indicated no observable excitatory effects of 12 atm abs in co
ntrol mice. The latency to myoclonus was significantly reduced by pres
sure in allylglycine-treated mice but not in mice treated with the oth
er convulsants. Latency to clonus was not significantly altered by pre
ssure, relative to latency at 1 atm abs heliox, for any drug tested. I
n conclusion, the present findings indicate that exposure to 12 atm ab
s heliox is not proconvulsant and, thus, the findings do not support t
he hypothesis that 12 atm abs heliox antagonizes ethanol indirectly vi
a an increase in central nervous system excitability.