Pharmacologic and behavioral responses of inbred C57BL/6J and strain 129/SvJ mouse lines

Gene-targeting technology is creating an explosion in the number of animals available with single gene mutations that affect the function of the centr al nervous system. Most gene-targeted mice are produced on a mixed genetic background of C57BL/6J and substrains of Strain 129. Understanding the beha vioral characteristics and responses to various drugs of these parental str ains is vital to interpreting data from gene-targeted mice. We directly com pared C57BL/6J and Strain 129/SvJ mouse lines on several behavioral paradig ms and in response to several hypnotic and anesthetic drugs. Compared to St rain 129/SvJ mice, C57BL/6J animals are more sensitive to the hypnotic effe cts of midazolam, zolpidem, and propofol, less sensitive to etomidate and e thanol, and do not differ in sensitivity to Ro15-4513 or pentobarbital. The se strains do not differ in their sensitivity to the motor ataxic effects o f the volatile anesthetics enflurane or halothane. However, Strain 129/SvJs are more sensitive to the immobilizing effects of halothane but not enflur ane. Motor coordination differs initially, but with repeated testing strain differences are no longer apparent. Strain 129/SvJ mite are more anxious o n the elevated plus maze and open-field activity assays. Thus, these mouse strains harbor polymorphisms that influence some, but not all, traits of in terest to behavioral neuroscientists. (C) 1999 Elsevier Science Inc.