Anxiogenic effect of pentylenetetrazole in a subconvulsive dose is accompanied by decreased cellular proliferation and neuronal NO-synthase expression in the posterior portion of the hippocampus

In our previous studies, we have found a suppressive effect of a single administration of pentylenetetrazole (PTZ) in a subconvulsive dose on cellular proliferation in the dentate gyrus. In the present work, we show that this decrease in proliferation develops after acute anxiogenic effect of PTZ and is present only in the posterior portion of the hippocampus, where a decrease in the number of neuronal NO synthase expressing cells has been also found. These changes are also accompanied by a decrease in the level of nNOS protein in the hippocampus. Taken together, these observations may indicate the possible involvement of nNOS in the suppression of cellular proliferation in the dentate gyrus of the posterior hippocampus during the development of the anxiogenic effect of PTZ.