Anxiolytic effect of kynuremic acid microinjected into the dorsal periaqueductal gray matter of rats placed in the elevated plus-mase test

The effect of kynurenic acid (20 to 19=60 nmol) microinkected into the dorsal periaqueductal gray matter was measured in rats placed in a elevated plus-maze. Microinjection of 160 nmol of kynurenic acid increased the percentages of open arm entries and of time spent in the open arms. Both of these measures may be considered indexes of anciolysis. Although kynurenic acid also invreased the total number of entries, analysis of covariance shows that the increase in open arm entries is independent of the effect on closed arm entries. Thus, the anxiolytic effect of kynurenic acid detected in the elevated plus-maze strengthens the proposal that glutamatergic neurons of the dorsal periaqueductal gray matter paly an important role in anxiety