We have searched for anatomical connections between the ventral mesencephalic tegmentum (VMT), including the dopaminergic cell group A10 and the locus coeruleus (LC) region. Tritiated leucine (120--220 nl) and horseradish peroxidase delivered by electrophoresis were injected in the VMT-A10 region. We have demonstrated, on the one hand bilateral projections from the VMT-A10 region to LC, and on the other hand a possible contralateral projection from LC to VMT-A10 region. These relationships, reported for the first time may have some important functional significance.