Skip to main content
Log in

Ultrastructural features of tyrosine-hydroxylase-immunoreactive afferents and their targets in the rat amygdala

  • Published:
Cell and Tissue Research Aims and scope Submit manuscript

Abstract.

Interrelations of tyrosine-hydroxylase-immunoreactive afferent fibres with neuronal elements were studied in central, basal and intercalated nuclei of the rat amygdaloid complex. Comparison with dopamine-β-hydroxylase-immunoreacted and phenylethanolamine-N-methyltransferase-immunoreacted parallel sections indicated that the tyrosine-hydroxylase immunoreaction labelled preferentially dopaminergic axons. At the elec- tron-microscopic level, the majority of tyrosine-hydroxylase-immunoreactive axons possessed small boutons containing small clear vesicles and contacting dendrites, spines or somata of amygdala neurons, forming mostly symmetric synapses. They were often directly apposed to or in the vicinity of unlabelled terminals synapsing on the same structure. Synaptic density was highest in the central lateral part of the central nucleus. In the central and basal nuclei labelled axons synapsed preferentially on small dendrites and dendritic spines, and on somata of a few neurons. A detailed study of the neuronal ultrastructure showed that innervated somata possessed the differential characteristics displayed by the predominant neuron types in the medial and central lateral central nucleus and resembled the typical projection neurons in the basal nuclei. In the paracapsular intercalated cell groups the majority of neurons possessed intense perisomatic innervation by immunoreactive terminals. The results suggest that tyrosine-hydroxylase-immunoreactive, predominantly dopaminergic amygdaloid afferent fibres preferentially modulate the effect of extrinsic inputs into neurons of the central and basal nuclei, while a nonselective regulation is exerted upon the output of paracapsular intercalated neurons. It is suggested that this innervation pattern may be important for the coordinated integration of extrinsic and intraamygdaloid connections and thus for balanced output of the structure.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

Author information

Authors and Affiliations

Authors

Additional information

Received: 23 May 1996 / Accepted: 24 October 1996

Rights and permissions

Reprints and permissions

About this article

Cite this article

Asan, E. Ultrastructural features of tyrosine-hydroxylase-immunoreactive afferents and their targets in the rat amygdala. Cell Tissue Res 288, 449–469 (1997). https://doi.org/10.1007/s004410050832

Download citation

  • Issue Date:

  • DOI: https://doi.org/10.1007/s004410050832

Navigation