Metrazol thresholds in inbred and non-inbred audiosensitive mice

Mice of the O'Grady strain which were inbred for susceptibility to audiogenic seizures were found to be more sensitive to pentamethylenetetrazol (Metrazol) convulsions than mice of the parent Swiss-Webster strain from which they were originally derived. A dose of 35 mg/kg Metrazol was required to produce a 50% convulsive response (CD50) in O'Grady mice and 50 mg/kg in the control parent strain. No differences in convulsive thresholds to Metrazol were obtained, however, between untreated Swiss-Webster mice and mice of the same strain made audiosuseptible by rubidium chloride intake or magnesium deficiency.