Early X-irradiation of rats. 1. Methodological description and morphological observations on the olfactory bulb

X-ray irradiation of rats in utero and during early postnatal days was performed using low, fragmented doses from a 60Co radiation source. Different radiation schedules were applied in order to impair the development of certain neurons. The effect of radiation on the main olfactory bulb was characterized in several ways. Early X-ray irradiation resulted in retardation of dams and young pups and an underdevelopment of the bulb and its main histological layers, especially the granule cell and external plexiform layers, but a disturbed glomerular development was also apparent. The resulting damage was proportional to the magnitude of the irradiation. The present technique seems to be useful in eliciting damage in separate populations of pre- or postnatally forming neurons.