Neuroleptanesthesia for the guinea pig. An ideal anesthetic procedure for long-term physiological studies of the cochlea.

The guinea pig is notoriously difficult to anesthetize with conventional agents. Cardiorespiratory depression by general depressant anesthetic agents can render the cochlea abnormal. I report a technique that uses the specific neuroleptic and analgesia properties of the agents droperidol and phenoperidine, respectively, in combination with small doses of pentobarbital sodium, which is required only to produce unconsciousness. These agents can be given intraperitoneally, intramuscularly, or intravenously. The regimen allows performance of substantial surgery (including intracranial) and long-term (minimum, six to ten hours) physiological studies, such as those on the cochlea, with excellent cardiorespiratory stability. The method has been in continuous use in this laboratory since 1974 for single-fiber recordings from the cochlear nerve of normal and kanamycin-treated guinea pigs. This method has proved to be substantially more effective than use of pentobarbital, thiopental sodium, urethan, chloralose, or ketamine alone.