Pentobarbital-induced changes in the mouse brainstem auditory evoked potential as a function of click repetition rate and time postdrug.

The effects of pentobarbital (80 mg/kg, i.p.) and saline injections on the BAEP were studied in 10 adult female BDF1 mice. Pentobarbital anesthesia induced statistically significant increases in the amplitudes and latencies of various BAEP components relative to preinjection and saline control values. These pentobarbital-induced changes were maximal shortly after drug administration and dissipated over time in a pattern similar to a drug elimination curve. Since pentobarbital and fast stimulus repetition rates are considered to be 'synaptic stressors', it was predicted that pentobarbital anesthesia and click repetition rate would have combined effects on the BAEP. This prediction was partially supported in that pentobarbital-induced changes in P4 amplitude and latency were significantly dependent on click repetition rate. The pentobarbital-induced effects on earlier BAEP components, however, proved to be largely independent of click rate. Pentobarbital-associated changes in the BAEP were not due to such factors as core temperature changes, circadian variations, and stress. The importance of anesthetic-induced changes in the BAEP for clinical and experimental studies is discussed.