Amygdaloid input to transiently tyrosine hydroxylase immunoreactive neurons in the bed nucleus of the stria terminalis of the rat.

Several studies have reported transient expression of tyrosine hydroxylase in a subpopulation of neurons in the bed nucleus of stria terminalis of preadolescent rats. The tyrosine hydroxylase immunoreactive (TH) neurons, which are of small to medium size and often display a typical bipolar configuration, are confined to the intermediate part of the lateral bed nucleus. By the use of a combination of experimental tracer techniques and immunocytochemical methods, we have demonstrated that these neurons receive a significant number of amygdaloid afferents, which establish mostly symmetric synaptic contacts on the cell bodies and sparsely spined dendritic shafts of the TH neurons. TH neurons also receive a small number of tyrosine hydroxylase-positive terminals of unspecified origin.