Prenatal Exposure to Classical Music Improves Learning and Memory in Adult Rats

Background: Exposure to music during pregnancy enhances brain development and improves learning in neonatal rats. Methods: In these experiments, we examined the effects of exposure to silence, hard rock, classical, and rap music in utero plus 60 days postpartum on learning and memory in adult Wistar rats. Passive avoidance learning (PAL) was assessed at age 60 days, and a retention test was done 24 hours after training. Elevated plus maze (EPM) was also used as a standard behavioral task for assessing the effects of music therapy on anxiety. Furthermore, we measured serum corticosterone levels and adrenal weight at the end of experiments to show the possible effect of stress on the rats’ behavior. Results: Hard rock music impaired acquisition, increasing the number of trials to acquisition in PAL task. Hard rock music also impaired the retrieval process by decreasing step-through latency and increasing time spent in the dark compartment during the retention trial. Further, in the hard rock group, there were increases in serum corticosterone and adrenal weight of rats. Classical music, in turn, improved acquisition learning and retention memory and decreased serum corticosterone levels compared to the silence group. Rats’ exposure to rap music did not show any significant change in acquisition and retrieval processes compared to the silence group. In the EPM task, classical music exposure had anxiolytic-like effects revealed in an increase in the number of entries into open arms and time spent in the open arms. However, in this task, hard rock music induced an anxiogenic effect. Conclusions: Prenatal and postnatal exposure to music improves PAL and memory in adult rats. The effects of music therapy with classical music might be related to stress reduction by lowering corticosterone as a stress biomarker or anxiolytic effects; this deserves further examination.

86 Evaluation of the effect of prenatal transportation stress on endocrine and immune tissues of neonatal Brahman calves

The objective of this experiment was to evaluate whether prenatal transportation stress (PNS) affects the weight of endocrine and immune tissues of calves. Mature Brahman cows inseminated to a single Brahman sire in 2018 were assigned to be either Control (n = 35; not transported) or PNS (n = 37; 2 h of transportation at 60, 80, 100, 120, and 140 ± 5 d of gestation). Of the calves born in 2019, 16 Control (8 bulls and 8 heifers) and 16 PNS (8 bulls and 8 heifers) calves were studied. Pen score, body weight, and blood samples were obtained from calves at 25 ± 2 d of age. At that time, calves were euthanized by barbiturate overdose in order to collect tissues (brain, pituitary and adrenal glands, spleen and thymus). Tissues were trimmed and weighed. Serum cortisol was determined by RIA. Data were analyzed using ANOVA, GLM, and CORR procedures of SAS with body weight at sample collection as a covariate. Whole pituitary weight tended (P = 0.08) to be greater in females compared to males, whereas anterior pituitary weight tended (P = 0.06) to be greater in PNS. Whole brain weight was greater (P < 0.01) in males. The interaction of treatment and sex on whole brain weight of PNS tended (P = 0.09) to fall between that of the Control females and Control males. Whole pituitary weight was positively correlated with total adrenal weight (r = 0.32; P = 0.08). Total thymus weight positively correlated with whole brain and total adrenal weight (r = 0.43 and 0.41, respectively; P < 0.05). Serum cortisol was negatively correlated with spleen weight and total immune tissue weight (r = -0.37 and -0.38, respectively; P < 0.05). Results suggest next steps should include a closer look at function of immune tissues by studying PNS effect on thymus response to immunization.

Correlation Between Telomere Attrition of Zona Fasciculata and Adrenal Weight Reduction in Older Men

Context Although numerous theories are reported on sex differences in longevity, the underlying biological mechanisms remain unknown. We previously reported that telomere length in the zona reticularis cells of the human adrenal cortex was significantly longer in older than that in younger subjects. However, we could not evaluate sex differences in the telomere lengths. Objective To compare the telomere lengths of adrenocortical and adrenal medullar cells between men and women from infancy through older adulthood. Methods Adrenal glands of 30 male (aged 0 to 100 years) and 25 female (aged 0 to 104 years) autopsied subjects were retrieved from autopsy files. Using quantitative fluorescence in situ hybridization, relative telomere lengths were determined in the parenchymal cells of the 3 adrenocortical zones and medulla. Age-related changes in the weight of adrenal glands were also investigated. Main results Older male subjects (aged 65 years or older) had significantly shorter telomere lengths in zona fasciculata (ZF) cells compared to the corresponding female subjects. In men, older subjects exhibited a significant age-related reduction in adrenal weight; however, no age-related changes in adrenal weight were detected in women. Conclusion Telomere attrition of ZF cells was correlated with adrenal weight reduction in older men but not in older women, suggesting a decreased number of ZF cells in older men. This may help us understand the possible biological mechanisms of sex difference in longevity of humans.

Impact of Centella Asiatica Extract on Memory and Adrenal Weight after Chronic Stress on Spraque Dawley rats

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Developmental Programming of Capuchin Monkey Adrenal Dysfunction by Gestational Chronodisruption

In the capuchin monkey (Cebus apella), a new-world nonhuman primate, maternal exposure to constant light during last third of gestation induces precocious maturation of the fetal adrenal and increased plasma cortisol in the newborn. Here, we further explored the effects of this challenge on the developmental programming of adrenal function in newborn and infant capuchin monkeys. We measured (i) plasma dehydroepiandrosterone sulphate (DHAS) and cortisol response to ACTH in infants with suppressed endogenous ACTH, (ii) plasma DHAS and cortisol response to ACTH in vitro, and (iii) adrenal weight and expression level of key factors in steroid synthesis (StAR and 3β-HSD). In one-month-old infants from mothers subjected to constant light, plasma levels of cortisol and cortisol response to ACTH were twofold higher, whereas plasma levels of DHAS and DHAS response to ACTH were markedly reduced, compared to control conditions. At 10 months of age, DHAS levels were still lower but closer to control animals, whereas cortisol response to ACTH was similar in both experimental groups. A compensatory response was detected at the adrenal level, consisting of a 30% increase in adrenal weight and about 50% reduction of both StAR and 3β-HSD mRNA and protein expression and the magnitude of DHAS and cortisol response to ACTH in vitro. Hence, at birth and at 10 months of age, there were differential effects in DHAS, cortisol production, and their response to ACTH. However, by 10 months of age, these subsided, leading to a normal cortisol response to ACTH. These compensatory mechanisms may help to overcome the adrenal alterations induced during pregnancy to restore normal cortisol concentrations in the growing infant.

Prenatal corticosterone exposure programs sex-specific adrenal adaptations in mouse offspring

Maternal stress can impair foetal development and program sex-specific disease outcomes in offspring through the actions of maternally produced glucocorticoids, predominantly corticosterone (Cort) in rodents. We have demonstrated in mice that male but not female offspring prenatally exposed to Cort (33 µg/kg/h for 60 h beginning at E12.5) develop cardiovascular/renal dysfunction at 12 months. At 6 months of age, renal function was normal but male offspring had increased plasma aldosterone concentrations, suggesting that altered adrenal function may precede disease. This study investigated the long-term impact of prenatal exposure to Cort on adrenal growth, morphology and steroidogenic capacity as well as plasma Cort concentrations in offspring at postnatal day 30 (PN30), 6 months and 12 months of age. Prenatal Cort exposure decreased adrenal volume, particularly of the zona fasciculata, in male offspring at PN30 but increased both relative and absolute adrenal weight at 6 months of age. By 12 months of age, male Cort-exposed offspring had reduced absolute adrenal weight in association with increased adrenal plaque deposition (lipogenic pigmentation). Plasma Cort concentrations were elevated in male 6-month offspring but not at other ages. mRNA expression of Mc2r (ACTH receptor) was increased in males at PN30, and Cyp11a1 expression was decreased at 6 and 12 months of age. There were no changes in the adrenals of female Cort-exposed offspring. This study demonstrates that prenatal Cort exposure induces offspring adrenal gland dysfunction in an age- and sex-specific manner, which may contribute to long-term programmed disease in male offspring after maternal stress.