Transcranial ultrasound modulates ketamine-xylazine effects in mice.

FABIAN ACQUATICCI; JUAN FRANCISCO GUARRACINO; SERGIO GWIRC; ADRIANA LOSAVIO; SERGIO LEW

Huerta Grande

Congreso; XXIX Congreso Anual de la Sociedad Argentina de Investigacion en Neurociencias; 2014

Sociedad Argentina de Investigacion en Neurociencias

Pulsed application of low intensity ultrasound waves induces microscopic vibrations which change brain tissue excitability, providing new means for non-invasive and localized functional brain stimulation and consciousness alterations. We used a 445 KHz immersion ultrasound transducer coupled to the CF-1 mice head (n=4) with ultrasound gel. Sonication protocol consisted of a tone burst of 0.5 ms and pulse repetition frequency of 1 kHz applied for 500 ms. Sonication began 15 minutes after the ketamine (80 mg/kg i.p.)-xylazine (10 mg/kg i.p.) injection and was delivered at 0.5 Hz until the onset of voluntary animal movements. A unique set of mice was put under this procedure and tested for different ultrasound intensities (150 mW/cm2, 300 mW/cm2, 450 mW/cm2 and 600 mW/cm2) with an inter-session time of one week. Although lower intensities (300 mW/cm2) were able to produce motor responses they failed to alter anesthesia duration. However, intensities higher than 600 mW/cm2 (Ispta, corresponding Isppa=1.2 W/cm2) altered anesthetic effects reducing recovery times from anesthesia in 20 min +/- 6min (mean +/- s.e.m) as measured by the time to the onset of voluntary movement. Together with the fact that brain stimulation can be assessed in a non-invasive form, our results contribute to a wider range of anesthesia recovery procedures and minimally consciousness state research.