Neuron somal size is decreased in the lateral amygdalar nucleus of subjects with bipolar disorder

Neuron somal size is decreased in the lateral amygdalar nucleus of subjects with bipolar disorder

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J Psychiatry Neurosci 2007;32(3):203-10

Yarema B. Bezchlibnyk, PhD; Xiujun Sun, MB; Jun-Feng Wang, MB, PhD; Glenda M. MacQueen, MD, PhD; Bruce S. McEwen, PhD; L. Trevor Young, MD, PhD

Bezchlibnyk, Sun and Wang — The Vivian Rakoff Mood Disorders Lab, Centre for Addiction and Mental Health, Toronto,Ont.; Wang and Young — Department of Psychiatry, University of Toronto, Toronto, Ont.; MacQueen — Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ont.; McEwen — The Harold and Margaret Milliken Hatch Laboratory of Neuroendocrinology, The Rockefeller University, New York, NY; Young — Department of Psychiatry, University of British Columbia, Vancouver BC.

Abstract

Objective: Morphometric studies of postmortem brains from subjects with mood disorders have reported altered density of glial cells in the amygdala; however, the nuclear regions have not been examined individually.
Methods: We assessed the size and density of both neuronal and glial cells in discrete amygdalar nuclei in postmortem sections from subjects with major depressive disorder, bipolar disorder (BD) and schizophrenia and from nonpsychiatric control subjects. Three adjacent Nissl-stained sections were examined from each individual.
Results: We report significantly decreased neuron somal size in the lateral amygdalar nucleus (LAN) and the accessory basal parvocellular nucleus (ABPC) in subjects with BD, relative to control subjects. These changes in cellular morphology were most prominent in the LAN in sections obtained from the left hemisphere.
Conclusions: These findings add to increasing evidence for neuropathological changes in the amygdala of subjects with BD and specifically implicate the LAN and ABPC in this disorder.

Résumé

Objectif : Des études morphométriques réalisées postmortem sur le cerveau de sujets atteints de troubles de l’humeur ont signalé une altération de la densité des cellules gliales des amygdales, mais les régions nucléaires n’ont pas été examinées individuellement.
Méthodes : Nous avons évalué la taille et la densité des cellules neuronales et gliales des noyaux amygdaliens discrets dans des coupes postmortem provenant de sujets atteints de trouble dépressif majeur, de trouble bipolaire et de schizophrénie, ainsi que de sujets témoins non psychiatrisés. On a examiné trois coupes adjacentes de chaque sujet, révélées par coloration de Nissl.
Résultats : Nous signalons une diminution importante de la taille du soma neuronal dans le noyau amygdalien latéral et le noyau parvocellulaire central accessoire chez les sujets atteints de trouble bipolaire par rapport aux sujets témoins. Ces changements de la morphologie cellulaire étaient les plus évidents dans le noyau amygdalien latéral des coupes tirées de l’hémisphère gauche.
Conclusions : Ces constatations ajoutent aux données de plus en plus nombreuses sur les changements neuropathologiques qui surviennent dans les amygdales de sujets atteints de trouble bipolaire et mettent en cause spécifiquement le noyau amygdalien latéral et le noyau parvocellulaire central accessoire dans ce trouble.


Medical subject headings: bipolar disorder, mood disorders, lithium, neuropsychiatry.

Competing interests: None declared.

Acknowledgements: Thanks to the Stanley Foundation Brain Bank and Drs. M. Knable, E.F. Torrey, M. Webster and R. Yolken for providing the postmortem brain tissue. This research was funded by Canadian Institutes for Health Research grant MOP-14998 and the Stanley Medical Research Institute. Dr. Bezchlibnyk is supported by an Ontario Graduate Scholarship.

Contributors: Drs. Bezchlibnyk, Wang, MacQueen, McEwen and Young designed the study. Drs. Bezchlibnyk and Sun aquired the data, and Dr. Bezchlibnyk analyzed it. Dr. Bezchlibnyk wrote the article, and Drs. Sun, Wang, MacQueen, McEwen and Young revised it. All authors gave final approval for the article to be published.

Submitted July 11, 2006; Revised Oct. 12, 2006; Accepted Nov. 24, 2006

Correspondence to: Dr. L. Trevor Young, Department of Psychiatry, University of British Columbia, Vancouver, 2255 Wesbrook Mall, Vancouver BC V6T 2A1; trevor.young@ubc.ca