Adrenoreceptor development in rat cerebrum and the effects of ionizing radiation

Previous studies in the rat have shown that neonatal radiation alters certain aspects of CNS monoaminergic systems including altering cerebral norepinephrine levels [17]. To determine if cerebral adrenoreceptor development is also altered by neonatal ionizing radiation, a single dose of whole body gamma-radiation was administered to rats on postnatal day two. This treatment did not alter (3H)-dihydroalprenolol (beta adrenoreceptor) or (3H)-WB4101 (alpha1 adrenoreceptor) binding when cerebra from irradiated animals were compared to age-matched sham-irradiated controls on postnatal days 9, 15 and 35. In contrast, (3H)-yohimbine (alpha2-adrenoreceptor) binding was altered in gamma-irradiation, a change manifested on postnatal days 9, 15 and 35 by lower than normal receptor densities (pmoles/g wet weight of tissue) although no radiation-induced changes in K/sub D/ were apparent