The distribution of hippocampal and spinal projecting cells in the locus coeruleus of tottering mice.

Wheat germ agglutinin conjugated to horseradish peroxidase and Fast Blue were used as retrograde tracers to examine the distribution of coeruleohippocampal and coeruleospinal somata within the locus coeruleus of normal and tottering mutant mice. The distributions of these projection neuron populations in normal mice are similar to what has been found in other species, and the distributions of these projection neurons in tottering mice are indistinguishable from those in normal mice, in spite of the norepinephrine hyperinnervation of certain locus coeruleus targets, including the hippocampus, in the tottering mutant. These observations lend support to the notion that the defect in tottering acts fairly directly on mechanisms involved in the development of locus coeruleus axonal arbors within certain target regions.