Inhibitory and Multisynaptic Spines, and Hemispherical Synaptic Specialization in the Posterodorsal Medial Amygdala of Male and Female Rats

Author(s)

Brusco, Janaina ^{[1, 2]} ; Merlo, Suelen ^[1] ; Ikeda, Erika T. ^[3] ; Petralia, Ronald S. ^[2] ; Kachar, Bechara ^[2] ; Rasia-Filho, Alberto A. ^[4] ; Moreira, Jorge E. ^{[1, 3]}

Affiliation

^[1] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Neurosci & Behav, BR-14049900 Ribeirao Preto - Brazil

^[2] Natl Inst Deafness & Other Commun Disorders, NIH, Bethesda, MD 20892 - USA

^[3] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Cell & Mol Biol, BR-14049900 Ribeirao Preto - Brazil

^[4] Fed Univ Hlth Sci Porto Alegre, Dept Basic Sci Physiol, BR-90050110 Porto Alegre, RS - Brazil

• Document type: Journal article
• Source: JOURNAL OF COMPARATIVE NEUROLOGY; v. 522, n. 9, p. 2075-2088, JUN 15 2014.
• Web of Science Citations: 17

Abstract

The density of dendritic spines is sexually dimorphic and variable throughout the female estrous cycle in the rat posterodorsal medial amygdala (MePD), a relevant area for the modulation of reproductive behavior in rats. The local synaptic activity differs between hemispheres in prepubertal animals. Here we used serial section transmission electron microscopy to produce 3D reconstructions of dendritic shafts and spines to characterize synaptic contacts on MePD neurons of both hemispheres in adult males and in females along the estrous cycle. Pleomorphic spines and nonsynaptic filopodia occur in the MePD. On average, 8.6% of dendritic spines received inputs from symmetric gamma-aminobutyric acid (GABA)-immunoreactive terminals, whereas 3.6% received two synaptic contacts on the spine head, neck, or base. Presynaptic terminals in female right MePD had a higher density of synaptic vesicles and docked vesicles than the left MePD, suggesting a higher rate of synaptic vesicle release in the right MePD of female rats. In contrast, males did not show laterality in any of those parameters. The proportion of putative inhibitory synapses on dendritic shafts in the right MePD of females in proestrus was higher than in the left MePD, and higher than in the right MePD in males, or in females in diestrus or estrus. This work shows synaptic laterality depending on sex and estrous cycle phase in mature MePD neurons. Most likely, sexual hormone effects are lateralized in this brain region, leading to higher synaptic activity in the right than in the left hemisphere of females, mediating timely neuroendocrine and social/reproductive behavior. J. Comp. Neurol. 522:2075-2088, 2014. (c) 2013 Wiley Periodicals, Inc. (AU)

• FAPESP's process: 05/56447-7 - Research through images from high field magnetic resonance aimed at studies in humans
• Grantee: João Pereira Leite
• Support Opportunities: Inter-institutional Cooperation in Support of Brain Research (CINAPCE) - Thematic Grants
• FAPESP's process: 09/01571-6 - The postero-dorsal medial amigdala of rats during the estrus cycle: morfology, mRNA expression, synaptic proteins and laterality
• Grantee: Jorge Eduardo Moreira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 12/19011-0 - Dendritic spines in the posterodorsal medial amygdala of rats: morphology and connectivity
• Grantee: Jorge Eduardo Moreira
• Support Opportunities: Regular Research Grants
• FAPESP's process: 11/10753-0 - Neurogenesis and synaptic plasticity in the hippocampus of rats submitted to the maternal separation and enriched environment
• Grantee: Jorge Eduardo Moreira
• Support Opportunities: Regular Research Grants