Anatomy and Embryology

, Volume 211, Issue 6, pp 721–737

Nitric oxide synthase-containing neurons in the amygdaloid nuclear complex of the rat

  • K. G. Usunoff
  • D. E. Itzev
  • A. Rolfs
  • O. Schmitt
  • A. Wree
Original Article

DOI: 10.1007/s00429-006-0134-9

Cite this article as:
Usunoff, K.G., Itzev, D.E., Rolfs, A. et al. Anat Embryol (2006) 211: 721. doi:10.1007/s00429-006-0134-9

Abstract

The nitric oxide-producing neurons in the rat amygdala (Am) were studied, using reduced nicotinamide adenine dinucleotide phosphate diaphorase (NADPHd) histochemistry. Almost all nuclei of the Am contained NADPHd-positive neurons and fibers, but the somatodendritic morphology and the intensity of staining of different subpopulations varied. The strongly stained neurons displayed labeling of the perikaryon and the dendritic tree with Golgi impregnation-like quality, whilst the dendrites of the lightly stained neurons were less successfully followed. Many strongly positive neurons were located in the external capsule and within the intraamygdaloid fiber bundles. A large number of small, strongly stained cells was present in the amygdalostriatal transition area. In the Am proper, a condensation of deeply stained cells occurred in the lateral amygdaloid nucleus. In the basolateral nucleus, the strongly NADPHd-positive neurons were few, and were located mainly along the lateral border of the nucleus. These cells clearly differed from the large, pyramidal, and efferent cells. The basomedial nucleus contained numerous positive cells but most of them were only lightly labeled. A moderate number of strongly stained neurons appeared in the medial division of the central nucleus, and a larger accumulation of strongly positive cells was present in the lateral and the capsular divisions. The medial amygdaloid nucleus contained numerous moderately stained neurons and displayed the strongest diffuse neuropil staining in Am. In the nucleus of the lateral olfactory tract, the first layer contained only NADPHd-stained axons, in the second layer, there were numerous moderately stained cells, and in the third layer, a few but deeply stained neurons. From the cortical nuclei, the most appreciable number of stained neurons was seen in the anterior cortical nucleus. The anterior amygdaloid area contained numerous NADPHd-positive neurons; in its dorsal part the majority of cells were only moderately stained, whereas in the ventral part the neurons were very strongly stained. The intercalated amygdaloid nucleus lacked NADPHd-positive neurons but an appreciable plexus of fine, tortuous axons was present. In the intra-amygdaloid part of the bed nucleus of the stria terminalis (st) some lightly stained cells were seen but along the entire course of st strongly stained neurons were observed. Some Am nuclei, and especially the central lateral nucleus and the intercalated nucleus, display considerable species differences when compared with the primate Am. The age-related changes of the nitrergic Am neurons, as well as their involvement in neurodegenerative diseases is discussed.

Keywords

Amygdala Enzyme histochemistry Limbic system NADPH-diaphorase Nitrergic 

Abbreviations

AA

Anterior amygdaloid area

AAD

Anterior amygdaloid area, dorsal part

AAV

Anterior amygdaloid area, ventral part

ACo

Anterior cortical amygdaloid nucleus

Am

Amygdala, amygdaloid nuclear complex

AStr

Amygdalostriatal transition area

BL

Basolateral amygdaloid nucleus

BM

Basomedial amygdaloid nucleus

BST

Bed nucleus of the stria terminalis

BSTIA

Bed nucleus of the stria terminalis, intraamygdaloid division

Ce

Central amygdaloid nucleus

CeC

Central amygdaloid nucleus, capsular division

CeL

Central amygdaloid nucleus, lateral division

CeM

Central amygdaloid nucleus, medial division

Co

Cortical amygdaloid nuclei

DEn

Dorsal endopiriform nucleus

IM

Intercalated amygdaloid nucleus

iNOS

Inducible nitric oxide synthase

La

Lateral amygdaloid nucleus

LOT

Nucleus of the lateral olfactory tract

LOT 1

Nucleus of the lateral olfactory tract, first layer

LOT 2

Nucleus of the lateral olfactory tract, second layer

LOT 3

Nucleus of the lateral olfactory tract, third layer

Me

Medial amygdaloid nucleus

MeAV

Medial amygdaloid nucleus, anteroventral part

NADPHd

Nicotinamide adenine dinucleotide phosphate diaphorase

nNOS

Neuronal nitric oxide synthase

NO

Nitric oxide

NOS

Nitric oxide synthase

OT

Optic tract

PB

Phosphate buffer

PBS

Phosphate buffered saline

Pir

Piriform cortex

PLCo

Posterolateral cortical amygdaloid nucleus

PRh

Perirhinal cortex

st

Stria terminalis

VEn

Ventral endopiriform nucleus

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • K. G. Usunoff
    • 1
    • 2
    • 3
  • D. E. Itzev
    • 2
  • A. Rolfs
    • 4
  • O. Schmitt
    • 3
  • A. Wree
    • 3
  1. 1.Faculty of Medicine, Department of Anatomy and HistologyMedical UniversitySofiaBulgaria
  2. 2.Institute of PhysiologyBulgarian Academy of SciencesSofiaBulgaria
  3. 3.Faculty of Medicine, Institute of AnatomyUniversity of RostockRostockGermany
  4. 4.Faculty of Medicine, Department of NeurologyUniversity of RostockRostockGermany