Origin of cholinergic fibers in the basolateral nucleus of the amygdaloid complex by using sensitive double-labeling technique of retrograde biotinized tracer and immunocytochemistry.

Injection of biotin-wheat germ agglutinin into the basolateral nucleus of the amygdaloid complex of the rat labeled many neurons in the substantia innomionata, ventral pallidum, horizontal limb of the diagonal band, interstitial nucleus of the ansa lenticularis, and bed nucleus of the stria terminalis. Except for the labeled cells in the bed nucleus of the stria terminalis, simultaneous staining with antiserum against choline transferase (ChAT) showed that some of these neurons are ChAT-like immunoreactive. This highest density of the double-labeled cells was seen in the horizontal limb of the diagonal band and substantia innominata, less numerous in the ventral pallidum and a few double-labeled cells in the interstitial nucleus of the ansa lenticularis.