Date of Award


Document Type

Open Access Dissertation

First Advisor

Alexander J McDonald


The studies comprising this dissertation were designed to investigate the synaptic organization of norepinephrine and opioid system in the anterior subdivision of the basolateral nucleus of amygdala (BLa) in rat. Light and electron microscopy were combined with immunohistochemistry to determine the synaptic incidence and postsynaptic targets of noradrenergic axon terminals, to localize mu opioid receptor at the ultrastructural level and to determine whether there is convergence of norepinephrine inputs and enkephalin inputs in the BLa. It was determined that about half of the norepinephrine inputs formed synapses in the BLa and the main postsynaptic targets were small caliber CAMK+ dendritic shafts and spines of pyramidal cells in the BLa. It was determined that MOR+ profiles were found in both pre and postsynaptic profiles. The most frequent labeled structures were small caliber dendrites and terminals. Both symmetrical and asymmetrical synapses were formed by MOR+ terminals, but the asymmetrical ones were more commonly observed in the BLa. MOR+ terminals were mainly targeted spines and small distal dendrites. It was determined that there was very limited (11%) convergence between ENK+ and norepinephrine terminals. These studies will contribute to a better understanding of how the noradrenergic and opioid systems affect BLa neural activity, which is essential to unravel the underlying mechanisms of memory modulation.