Age-dependent changes in the medial prefrontal cortex and medial amygdala structure, and elevated plus-maze performance in the healthy male Wistar rats. (December 2020)

• Record Type: Journal Article
• Authors: Sotoudeh, N.; Namavar, M.R.; Zarifkar, A.; Heidarzadegan, A.R.
• Is Part Of: IBRO reports. Volume 9(2020)
• Page Start: 183
• Page End: 194
• Publication Date: 2020-12
• Subjects: Aging -- Anxiety -- Medial prefrontal cortex -- Amygdala -- Dendritic complexity -- Neuronal spatial distribution -- Stereology; Nervous system -- Periodicals; Brain -- Periodicals; Brain -- Research -- Periodicals; Nervous system; Brain -- Research; Brain; Neurology; Nervous System Physiological Phenomena; Electronic journals; Periodicals; Fulltext; Internet Resources; Periodicals; Periodical
• DOI: 10.1016/j.ibror.2020.08.002
• Languages: English
• ISSNs: 2451-8301

Abstract

Highlights: Aging increased amygdala volume, its neuron number, dendritic length and complexity. Old rats have larger neurons and more mature spines in the mPFC with less dendritic complexity. Old individual shows more anxiety than young one. Abstract: Aging affects different parts of the brain structure and function. These changes are associated with several age-related emotional alterations like anxiety that is regulated by the amygdala and medial prefrontal cortex (mPFC). Thus, this study aimed to explore the effects of aging on the morphology changes in these regions. Twenty male Wistar rats were assigned to young and old groups. The anxiety level was evaluated by elevated plus-maze. Then, their brains were removed, fixed, cut, and stained with Cresyl Violet or Golgi-Cox. In addition to the estimation of stereological parameters, dendrite complexity, and spatial distribution of the neurons in the mPFC and amygdala were evaluated. Aging increased the medial amygdala volume and its total number of neurons, but it did not have a significant effect on these parameters in the mPFC. Furthermore, the size of the neurons in the mPFC increased, whereas the total length of the dendrite and its complexity significantly decreased with aging in this structure and increased in the amygdala. Although aging did not significantly change the dendritic spine density in both regions, old rats showed a more mature spine in the mPFC and more anxiety-like behavior. In conclusion, the increase of anxiety in the old individuals could be attributed to structural changes in the morphology of the dendrite and neuron and its spatial distribution in the mPFC and amygdala. The findings of this study partly support this hypothesis.