Differential Role of Sex and Age in the Synaptic Transmission of Degus (Octodon degus)

Abstract

Octodon degus are a diurnal long-lived social animal widely used to perform longitudinal studies and complex cognitive tasks to test for physiological conditions with similitude in human behavior. They show a complex social organization feasible to be studied under different conditions and ages. Several aspects in degus physiology demonstrated that these animals are susceptible to environmental conditions, such as stress, fear, feeding quality, and isolation. However, the relevance of these factors in life of this animal depends on sex and age. Despite its significance, there are few studies with the intent to characterize neurological parameters that include these two parameters. To determine the basal neurophysiological status, we analyzed basic electrophysiological parameters generated during basal activity or synaptic plasticity in the brain slices of young and aged female and male degus. We studied the hippocampal circuit of animals kept in social ambient in captivity under controlled conditions. The study of basal synaptic activity in young animals (12–24 months old) was similar between sexes, but female degus showed more efficient synaptic transmission than male degus. We found the opposite in aged animals (60–84 months old), where male degus had a more efficient basal transmission and facilitation index than female degus. Furthermore, female and male degus develop significant but not different long-term synaptic plasticity (LTP). However, aged female degus need to recruit twice as many axons to evoke the same postsynaptic activity as male degus and four times more when compared to young female degus. These data suggest that, unlike male degus, the neural status of aged female degus change, showing less number or functional axons available at advanced ages. Our data represent the first approach to incorporate the effect of sex along with age progression in basal neural status.

Age-Dependent Behavioral and Synaptic Dysfunction Impairment Are Improved with Long-Term Andrographolide Administration in Long-Lived Female Degus (Octodon degus)

“…To determine whether the differences in the amount of elicited LTP were due to the synaptic status previous to TBS, we compared the FV amplitudes and fEPSP slopes of all the experiments used in the LTP analysis. We averaged them and plotted the correlations between these two parameters, as has been shown before [ 9 , 12 , 13 ]. In Figure 4 F, we plotted the averaged FV amplitudes and slopes before (enclosed symbols) and after TBS (symbols alone) of adult control females (empty circles) and aged control females (solid squares).…”

“…The use of Octodon degus as a neurological model has been extensively reported [ 5 , 10 , 11 , 12 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. The broad range of degus’ behavioral complexities, the similarities with the human aging process, and the biological mechanisms underlying synaptic deficiencies make degus a multifaceted model.…”

“…Degus suffer from the effects of aging on several physiological aspects, including reduced cognitive function and deficient synaptic activity that start at around three years old and worsen over time. We recently reported sex differences in a study that involves age progression in degus [ 12 ]. Interestingly, we found that female degus are strongly affected by age.…”

“…Instead, males recruited the same axonal terminals when young or aged, indicating that their synaptic mechanisms were not affected during age progression. These data showed a strong aging impact on the synaptic mechanisms of female degus [ 12 ].…”

Зміни Клінічного Та Гематологічного Статусів У Чілійських Білок Дегу За Наявності Цукрового Діабету

“…У природному середовищі у білок Дегу досить рідко розвивається цукровий діабет. Ймовірно, це є результатом дієти на природних пасовищах, багатих білками і низьким вмістом вуглеводів [11,[14][15][16][17].…”