Pentylenetetrazole (PTZ) is a central nervous system modulator that is used to experimentally induce seizures in animals. Subcutaneous PTZ has been used extensively to screen for compounds that block the production of nonconvulsive (absence or myoclonic) seizures. PTZ has diverse, site-specific effects in the brain. However, it is an antagonist of GABAA receptors and some drugs that block PTZ-induced seizures, including benzodiazepines, act at the GABAA receptor.