Noradrenergic system: effect of DSP4 and FLA-57 on ethanol intake in ethanol preferring rats.
Ethanol preferring rats (male Long-Evans; n = 6) were selected as drinking rats (DR) and treated with DSP4 (50 mg.kg-1 IP) at the end of the preference selection. Two more groups received DSP4 (50 mg.kg-1 IP) + the inhibitor of dopamine beta-hydroxylase FLA-57 (1 mg.kg-1.d-1 during two weeks), IP (n = 5) or FLA-57 alone (1 mg.kg-1.d-1 during two weeks IP) (n = 5). The control DR group (n = 6) received NaCl 0.9%. 3H-Noradrenaline uptake was studied at the 17th day of treatment in DR, treated or not with DSP4, and in ethanol naive rats treated (n = 6) or not (n = 6) with DSP4 (50 mg.kg-1, IP) DSP4 does not modify ethanol intake in DR, and both treated groups (DR or ethanol naive rats). 3H-Noradrenaline uptake was decreased (about 60%), both in cortex and hippocampus. But the association of FLA-57 and DSP4 decreases both ethanol and fluid intakes. It was suggested 1) that the 40% of intact neurons was able to compensate the DSP4-induced noradrenergic neurons destruction, 2) that the destruction of noradrenergic pathways (FLA-57 + DSP4) is associated with a decrease in ethanol intake but also in fluid intakes, suggesting finally 3) that the modulation of ethanol intake by the noradrenergic system was partial or indirect.