COMPARATIVE EFFECTS OF BRADYKININ AND ATRIAL-NATRIURETIC-FACTOR ON NEURONAL AND NONNEURONAL NORADRENALINE UPTAKE IN THE CENTRAL-NERVOUS-SYSTEM OF THE RAT

Binding sites of atrial natriuretic factor (ANF) and bradykinin (BDK) have been described in discrete areas of central nervous system of the rat. The interaction between ANF and BDK on noradrenaline (NA) uptake were studied in hypothalamus (Hyp) and medulla oblongata (MO). One hu ndred nM ANF in both regions and 100pM BDK in Hyp and 1nM BRD in MO in creased total NA uptake. Subthreshold concentrations of ANF (InM) reve rsed the effect of threshold concentrations of BDK in Hyp and MO. Non- effective concentrations of BRD did not modify the increase produced b y 100nM ANF in both central regions. Effective concentrations of ANF a nd BDK did not induce additive effect in total H-3-NA uptake neither i n Hyp nor in MO. Threshold concentrations of ANF and BDK increased onl y neuronal NA uptake in Hyp as well as MO. These results suggest an AN F-BDK interaction at the neuronal NA control mechanisms involved in th e regulation of blood pressure, electrolytes and water balances, and n euroendocrine processes.