The Anti-anesthetic Action of Idazoxan

抄録

A possible anti-anesthetic effect of idazoxan using the depth versus latency of cortical cellular response and somatosensory evoked potentials as indices of anesthesia was studied. With the administration of 10mg/kg (i.p.) idazoxan, a potent and selective α₂-adrenoceptor antagonist, to an anesthetized rat with 1.25-1.5g/kg (i.p.) urethane, the modal latency of somatosensory cortical responses to electrical stimulation of the forepaw (0-90V, 1Hz) was shortened to 87±3.6% (mean±S.D.; n=3) of the baseline value. The number of units firing increased by 259±98.5% (n=3). The combined parameter (1/L×P_i ; L, latency ; P_i, initial positive wave) of the somatosensory evoked potentials was enhanced to 125.0±16.2% (n=19) versus saline (98.9±25.6% ; n=18) during the desynchronized electroencephalogram (EEG). The initial negative component (N_i) of the somatosensory cortical response was increased to 192.0±83.1% (n=19) and 134.8±36.9% (n=19) during the synchronized and desynchronized EEG, respectively. Thus idazoxan appears to produce effects resembling a "lightening of anesthesia."This may provide the impetus for further studies on the possibility of using α₂-adrenoceptor antagonists in the recovery from certain types of anesthetic agents.