NEUROPEPTIDE-Y AND SOMATOSTATIN IMMUNOREACTIVITY IN THE RAT HIPPOCAMPUS AFTER MODERATE HYPOXIA

Transient moderate hypoxia has been previously shown to exert a potent protective role to subsequently applied convulsant drugs. We now inve stigated neuropeptide Y and somatostatin immunoreactivities seven days after moderate hypoxia (9% O-2 in N-2 for two times 8 h) in the hippo campus of the rat. A slight reduction of somatostatin immunoreactive c ells was observed in the hilus of the dorsal and ventral hippocampus. At the same time, the total number of neuropeptide Y immunoreactive ne urons was increased in this area due to a pronounced increase in stain ing of presumable basket cells. There was also increased staining of n europeptide Y positive fibers in the outer molecular layer. Our data s uggest activation of neuropeptide Y containing interneurons after a mo derate or a mild transient hypoxia. Activation of these inhibitory neu rons may contribute to the protective effect of this treatment.