“…Roth, Salzman, and Morganroth (1974) found increases in tyrosine hydroxylase activity in hippocampus after short-term stimulation of the locus coeruleus, a nuclear group containing noradrenergic cell bodies. Increases in striatal tyrosine hydroxylase activity also have been observed after short-term (Murrin, Morganroth, & Roth, 1974) and longterm (Schlehuber, Segal, & Spooner, 1975) stimulation of dopaminergic cell bodies in the substantia nigra. The possibility that tryptophan hydroxylase activity also may be influenced by nerve activity has been suggested by work in animals with spinal cord transection (e.g., Carlsson, 1974).…”