Synaptosomal uptake studies on recombinant inbred mice; neurotransmitter interaction and behavioral correlates

The uptake of noradrenaline, choline and GABA into whole brain synaptosomes from the mice inbred strains C57BL/6By, BALB/cBY, their reciprocal crosses and seven recombinant inbred strains derived from the F₂ crosses was measured in order to study the relation between different neurotransmitter systems and their possible correlations with behavioral parameters. Analysis of variance demonstrated significant differences in both V_max and K_m for each substrate between the inbred strains studied. Only the K_m for GABA uptake did not reach significance although a strong trend (P = 0.07) was apparent. For none of the uptake parameters clear strain distribution patterns were found. A positive phenotypic as well as genotypic correlation was found between the V_max and K_m for noradrenaline, choline and GABA uptake. A genetic analysis showed a positive correlation between the V_max for noradrenaline and choline uptake. Since prior to these neurochemical studies, all subjects were tested in a variety of behavioral paradigms, phenotypic and genotypic correlations between behavioral and neurochemical parameters could be calculated. The most consistent correlations were found between noradrenaline and choline uptake and water consumption and the preference ratio as measured in a conditioned tast aversion test.