Maternal and post-natal obesity alters long-term memory and hippocampal molecular signaling of male rat.

The aim of this study was to investigate whether maternal cafeteria ingestion interferes with long-term memory-related behaviors and hippocampal brain-derived neurotrophic factor (BDNF) signaling in the offspring, and if there is a cumulative effect with the exposure to cafeteria diet during the life-course of the pups. Female rats were fed a control (CON, n = 20) or cafeteria diet (CAF, n = 24) from their weaning to weaning of their offspring. After that, their male offspring were divided into 4 groups (CON-CON, n = 36; CON-CAF, n = 38, CAF-CON, n = 46 and CAF-CAF, n = 39) so that all litters ingested CON or CAF, irrespective of maternal diet.

Effects of exposure to a cafeteria diet during gestation and after weaning on the metabolism and body weight of adult male offspring in rats.

In the present study, we investigated whether maternal exposure to a cafeteria diet affects the metabolism and body composition of offspring and whether such an exposure has a cumulative effect during the lifetime of the offspring. Female rats were fed a control (CON) or a cafeteria (CAF) diet from their own weaning to the weaning of their offspring. At 21 d of age, male offspring were divided into four groups by diet during gestation and after weaning (CON-CON, CON-CAF, CAF-CON and CAF-CAF).

The role of AT1 receptor-mediated reproductive function in renovascular hypertension in male rats.

There is an association between hypertension and reproductive dysfunction. Angiotensin II (Ang II) is involved in the pathogenesis of hypertension and the regulation of reproduction. The present study aimed to determine whether the angiotensinergic system mediates the effects of hypertension on reproductive function in male rats subjected to a two-kidney, one-clip (2K1C) model.

Progesterone and maternal aggressive behavior in rats.

Females usually display low levels of aggressiveness; however, during lactation, the aggressive behavior against intruders to the nest area is an important component of the maternal behavioral repertoire. The present study aimed to analyze the influence of progesterone (P4) on the maternal aggressive behavior in rats. Lactating rat were ovariectomized on the first day after delivery and, on the 6th postpartum day, aggressive behaviors against a male intruder were recorded.

Effect of acute stress on sexual behavior in female rats: participation of the central angiotensinergic system.

Stress might influence the reproductive behavior in females, and central angiotensin II (Ang II) is a peptide that plays a role in stress response and in the modulation of sexual behavior. The medial amygdala (MeA), an important structure that regulates this behavior, is strongly involved in stress response. The aim of the present study was to evaluate the effect of acute restraint stress on the night of proestrus on sexual receptivity in female rats and the participation of Ang II and MeA in this effect.

Neonatal handling reduces renal function in adult rats.

Background/aims: To evaluate the effects of neonatal handling on hydroelectrolytic balance in adult rats.

Methods: The litters were divided into two groups: nonhandled and handled. The procedure consisted of handling the pups for 1 min/day in the first 10 days postnatally.

Effects of neonatal handling on social memory, social interaction, and number of oxytocin and vasopressin neurons in rats.

Early-life environmental events can induce profound long-lasting changes in several behavioral and neuroendocrine systems. The neonatal handling procedure, which involves repeated brief maternal separations followed by experimental manipulations, reduces stress responses and sexual behavior in adult rats. The purpose of this study was to analyze the effects of neonatal handling on social behaviors of male and female rats in adulthood, as manifest by the results of social memory and social interaction tests.

Effects of neonatal handling on central noradrenergic and nitric oxidergic systems and reproductive parameters in female rats.

Early-life environmental events that disrupt the mother-pup relationship may induce profound long-lasting changes on several behavioral and neuroendocrine systems. The neonatal handling procedure, which involves repeated brief maternal separations followed by experimental manipulations, reduces sexual behavior and induces anovulatory estrous cycles in female rats. On the afternoon of proestrus, neonatally handled females show a reduced surge of luteinizing hormone (LH) and an increased content of gonadotropin-releasing hormone in the medial preoptic area (MPOA).

Effects of acute stress on the day of proestrus on sexual behavior and ovulation in female rats: participation of the angiotensinergic system.

Physical or emotional stress can affect the female reproductive physiology and angiotensin II (Ang II) is a hormone that participates in the stress response and also in the control of reproductive hormones. The present study aimed at evaluating the effects of acute stress in the morning and afternoon of proestrus on sexual behavior and ovulation and the participation of Ang II in the stress-induced effects. Female rats with regular estrous cycles were used.

Effects of neonatal novelty exposure on sexual behavior, fear, and stress-response in adult rats.

Environmental stimuli in early life may result in permanent behavioral and physiological changes. Present study evaluated the effects of exposing pups to a novel environment on behaviors (open-field test and sexual behavior) and prolactin stress-responses in adult male rats. Half of a litter was daily removed outside (OUT) from the nest and stimulated by handling for 3 min, while the other half remained inside (IN) the nest and was also handled for the same period during the first 10 days postpartum.

Effects of renovascular hypertension on reproductive function in male rats.

Objective: The present study investigated the effects of renovascular hypertension (2K/1C model) on the reproductive function of male rats, represented by sexual behavior, plasma prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone, and spermatogenesis.

Methods: The present experiments were performed to investigate the reproductive function of 2K/1C male Wistar rats and compare with 2K/1C male rats successfully treated for hypertension with nifedipine and was divided in the following groups: (1) Sham+V (n=10): Sham-operated males with vehicle used; (2) Sham+N (n=13): Sham-operated males treated with nifedipine (10 mg/kg/day); (3) 2K/1C+V (n=14): 2K/1C-operated males with vehicle used; and (4) 2K/1C+N (n=16): 2K/1C-operated males treated with nifedipine.

Results: The data indicated an association between hypertension induced by the 2K/1C model and reduction of reproductive function, as demonstrated by an impairment of sexual behavior, higher plasma PRL and lower plasma testosterone and FSH.

Estradiol and progesterone modulation of angiotensin II receptors in the arcuate nucleus of ovariectomized and lactating rats.

The expression of angiotensin II (Ang II) receptors in the brain is modulated by estradiol and progesterone. Considering that Ang II plays a critical role in controlling prolactin secretion and that neurons in the arcuate nucleus (ARC) are the main regulator of this function, the present study aimed to evaluate ARC Ang II receptor binding in 2 experimental models with different estradiol and progesterone plasma levels. Animals were divided into 4 groups: ovariectomy (OVX) plus oil vehicle, OVX plus estradiol and progesterone replacement, lactating rats on day 7 postpartum, and lactating rats on day 20.

Changes in alpha-estradiol receptor and progesterone receptor expression in the locus coeruleus and preoptic area throughout the rat estrous cycle.

We have previously shown that the locus coeruleus (LC) is essential for triggering surges of LH. Since LC neurons are responsive to estradiol, which induces progesterone receptor (PR) expression, this study aimed to investigate whether LC neurons express the alpha-estradiol receptor (alphaER) and PR as well as comparing such responses to that observed in the preoptic area (POA). Female rats were perfused at 10, 14 and 16 h on each day of the estrous cycle, and a blood sample was collected for estradiol, progesterone and LH measurements.

Neonatal handling induces alteration in progesterone secretion after sexual behavior but not in angiotensin II receptor density in the medial amygdala: implications for reproductive success.

Neonatal handling affects the hypothalamus-pituitary-gonadal axis in female rats. Indeed, postnatal handling induces anovulatory estrous cycles and decreases sexual receptiveness. On the other hand, Angiotensin II (Ang II) infused into the medial amygdala (MeA) reduces sexual behavior in male and female rats.

Neonatal handling reduces angiotensin II receptor density in the medial preoptic area and paraventricular nucleus but not in arcuate nucleus and locus coeruleus of female rats.

Neonatal handling alters the hypothalamic-pituitary-adrenal (HPA) axis and the hypothalamic-pituitary-gonads axis (HPG) in adult animals, and angiotensin II (Ang II) modulates the functions in these axes. We tested whether neonatal handling could change the density of Ang II receptors in some central areas in female rats. Results showed decreased density of the Ang II receptors in the medial preoptic area (MPOA) and hypothalamic paraventricular nucleus (PVN) of the neonatal handled group.

Angiotensin II receptors are upregulated by estradiol and progesterone in the locus coeruleus, median preoptic nucleus and subfornical organ of ovariectomized rats.

Angiotensin II (Ang II) receptors in specific brain areas and in the anterior pituitary are controlled by reproductive hormones. Since Ang II also plays a role in controlling reproductive functions, such as luteinizing hormone and prolactin secretion, the objective of the present study was to evaluate the regulation of Ang II receptors by estradiol (E(2)) and progesterone (P) in areas of the brain involved in homeostatic and reproductive functions, such as the locus coeruleus (LC), median preoptic nucleus (MnPO) and subfornical organ (SFO). Adult female rats were ovariectomized under anesthesia and divided into 2 groups after 2 weeks: OVX plus E(2)/P replacement (OVXE(2)P) and OVX plus oil vehicle (OVX).

Angiotensin II receptors in the arcuate nucleus mediate stress-induced reduction of prolactin secretion in steroid-primed ovariectomized and lactating rats.

Angiotensin II (Ang II) is a peptide that exerts an inhibitory effect upon pituitary prolactin (PRL) release through the hypothalamic arcuate nucleus (ARC). Since both PRL and Ang II are known to be affected by stress, the experiments reported here were conducted to investigate the possible participation of Ang II in the stress-induced response of PRL in situations in which pre-stress PRL levels are high, as during the PRL surge induced by estradiol (E(2)) and progesterone (P) in ovariectomized rats (OVXE(2)P) and lactating females on day 7 post-partum. Adult female rats were stereotactically implanted with bilateral guide-cannulae in the ARC; 3 days later, they were microinjected with saline or losartan and, after a 15-min interval, they were submitted to stress by ether inhalation during 1 min.