Divergent levels of anxiety in mice selected for differences in sensitivity to a convulsant agent

Spontaneous behavior patterns were assessed in eight different behavioral s ituations in two lines of mice, BR and BS, previously selected for their se nsitivity to an anxiogenic benzodiazepine (BZ) receptor inverse agonist, Me thyl beta -carboline-3-carboxylate (beta -CCM). BR is highly resistant, and BS, highly sensitive to beta -CCM-induced seizures. Tests used included an assessment of general locomotor activity, several situations classically u sed for measuring fear-motivated behaviors (open field, thigmotaxis, elevat ed plus-maze, light-dark discrimination, staircase), a test for measuring e xploration (holeboard), and a test for measuring nociception (hot-plate). I n the absence of beta -CCM, the results provide evidence of reduced motor a ctivity and higher levels of anxiety in the BR line as compared to the BS l ine. (C) 2000 Elsevier Science Inc. All rights reserved.