Advances in Medicine and Biology. Volume 107

In: Advances in Medicine and Biology. Vol. 107 ISBN: 978 - 1 - 53610 - 056 - 3
Editor: Leon V. Berhardt © 201 6 Nova Science Publishers, Inc.

Chapter 6

DYNAMIC AND INTEGRATED SYNAPTIC

PROCESSING IN THE SEX-STEROID

SENSITIVE MEDIAL AMYGDALA

OF FEMALE RATS

Mariana Zancan and Alberto A. Rasia-Filho

Federal University of Health Sciences of Porto Alegre,

Dept. Basic Sciences/Physiology, Porto Alegre, RS, Brazil; and,

Federal University of Rio Grande do Sul, Graduation Program

in Neurosciences, Porto Alegre, RS, Brazil

ABSTRACT

The posterodorsal medial amygdala (MePD) is a sexually dimorphic

area that contains one of the highest concentration of gonadal hormone

receptors in the rat brain. It modulates the timely display of reproductive

behavior in both male and female rats. Dynamic changes affect the local

synaptic processing along the estrous cycle. These changes are evident in

the number of synapses made directly on dendritic shafts or the complex

modulation of the density and the shape of dendritic and somatic spines

during the short-term proestrus phase, when the levels of estradiol and

progesterone reach a peak in circulation. That is, the MePD of females in

proestrus has an increase in the number and diversity of somatic spines.

In contrast, there is a marked reduction in the density of dendritic spines

during this same phase. Spines are specialized postsynaptic neuronal