Androgens Enhance Adult Hippocampal Neurogenesis in Males but Not Females in an Age-Dependent Manner.

Androgens (testosterone and DHT) increase adult hippocampal neurogenesis by increasing survival of new neurons in male rats and mice via an androgen receptor pathway, but it is not known whether androgens regulate neurogenesis in female rats and whether the effect is age-dependent. We investigated the effects of DHT, a potent androgen, on neurogenesis in young adult and middle-aged male and female rats. Rats were gonadectomized and injected with the DNA synthesis marker bromodeoxyuridine (BrdU).

Premarin has opposing effects on spatial learning, neural activation, and serum cytokine levels in middle-aged female rats depending on reproductive history.

Menopause is associated with cognitive decline, and hormone therapies (HTs) may improve cognition depending on type and timing of HTs. Previous parity may influence cognition in later life. We investigated how primiparity and long-term ovariectomy influence cognition, neurogenesis, hormones, cytokines, and neuronal activation in middle-aged rats in response to Premarin, an HT.

Maternal exercise increases but concurrent maternal fluoxetine prevents the increase in hippocampal neurogenesis of adult offspring.

Treating postpartum depression (PPD) with pharmacological antidepressants like fluoxetine (FLX) is complicated because these drugs can remain active in breast milk and potentially affect infant development. Alternatively, non-pharmacological treatments such as exercise are associated with beneficial effects on infant development but its potential ability to counter the effects of PPD are largely unknown. To investigate this, we treated dams with corticosterone (CORT) or vehicle (sesame oil) from postpartum days 2-25 to model PPD.

Voluntary running influences the efficacy of fluoxetine in a model of postpartum depression.

Postpartum depression affects approximately 15% of mothers. Unfortunately, treatment options for postpartum depression are limited. Pharmacological antidepressants such as fluoxetine (FLX) can be controversial due to inconclusive evidence of efficacy during the postpartum and concerns of neonatal exposure to antidepressants.

Mechanistic Characterization of Escherichia coli l-Aspartate Oxidase from Kinetic Isotope Effects.

l-Aspartate oxidase, encoded by the nadB gene, is the first enzyme in the de novo synthesis of NAD in bacteria. This FAD-dependent enzyme catalyzes the oxidation of l-aspartate to generate iminoaspartate and reduced flavin. Distinct from most amino acid oxidases, it can use either molecular oxygen or fumarate to reoxidize the reduced enzyme.

Sex-dependent effects of maternal corticosterone and SSRI treatment on hippocampal neurogenesis across development.

Background: Postpartum depression affects approximately 15% of mothers and represents a form of early life adversity for developing offspring. Postpartum depression can be treated with prescription antidepressants like fluoxetine (FLX). However, FLX can remain active in breast milk, raising concerns about the consequences of neonatal FLX exposure.

Parity modifies the effects of fluoxetine and corticosterone on behavior, stress reactivity, and hippocampal neurogenesis.

The postpartum confers considerable risk for developing depression. Depressed patients have elevated cortisol concentrations and impaired hypothalamic-pituitary-adrenal (HPA) axis negative feedback. Chronic stress or corticosterone (CORT) induces a depressive-like phenotype in rodents, including during the postpartum.

Testosterone has antidepressant-like efficacy and facilitates imipramine-induced neuroplasticity in male rats exposed to chronic unpredictable stress.

Hypogonadal men are more likely to develop depression, while testosterone supplementation shows antidepressant-like effects in hypogonadal men and facilitates antidepressant efficacy. Depression is associated with hypothalamic-pituitary-adrenal (HPA) axis hyperactivity and testosterone exerts suppressive effects on the HPA axis. The hippocampus also plays a role in the feedback regulation of the HPA axis, and depressed patients show reduced hippocampal neuroplasticity.

Enzymatic Depletion of the Polysialic Acid Moiety Associated with the Neural Cell Adhesion Molecule Inhibits Antidepressant Efficacy.

Antidepressant drugs are too often ineffective, the exact mechanism of efficacy is still ambiguous, and there has been a paucity of novel targets for pharmacotherapy. In an attempt to understand the pathogenesis of depression and subsequently develop more efficacious antidepressant drugs, multiple theories have been proposed, including the modulation of neurotransmission, the upregulation of neurogenesis and neurotrophic factors, normalizing hypothalamic-pituitary-adrenal reactivity, and the reduction of neuroinflammation; all of which have supporting lines of evidence. Therefore, an ideal molecular target for novel pharmaceutical intervention would function at the confluence of these theories.

Maternal postpartum corticosterone and fluoxetine differentially affect adult male and female offspring on anxiety-like behavior, stress reactivity, and hippocampal neurogenesis.

Postpartum depression (PPD) affects approximately 15% of mothers, disrupts maternal care, and can represent a form of early life adversity for the developing offspring. Intriguingly, male and female offspring are differentially vulnerable to the effects of PPD. Antidepressants, such as fluoxetine, are commonly prescribed for treating PPD.

Sex and strategy use matters for pattern separation, adult neurogenesis, and immediate early gene expression in the hippocampus.

Adult neurogenesis in the dentate gyrus (DG) plays a crucial role for pattern separation, and there are sex differences in the regulation of neurogenesis. Although sex differences, favoring males, in spatial navigation have been reported, it is not known whether there are sex differences in pattern separation. The current study was designed to determine whether there are sex differences in the ability for separating similar or distinct patterns, learning strategy choice, adult neurogenesis, and immediate early gene (IEG) expression in the DG in response to pattern separation training.

Hippocampal learning, memory, and neurogenesis: Effects of sex and estrogens across the lifespan in adults.

This article is part of a Special Issue "Estradiol and Cognition". There are sex differences in hippocampus-dependent cognition and neurogenesis suggesting that sex hormones are involved. Estrogens modulate certain forms of spatial and contextual memory and neurogenesis in the adult female rodent, and to a lesser extent male, hippocampus.

Estradiol and GPER Activation Differentially Affect Cell Proliferation but Not GPER Expression in the Hippocampus of Adult Female Rats.

Estradiol increases cell proliferation in the dentate gyrus of the female rodent but it is not known whether the G protein-coupled estrogen receptor (GPER), a membrane receptor, is involved in this process, nor whether there are regional differences in estradiol's effects on cell proliferation. Thus, we investigated whether estradiol exerts its effects on cell proliferation in the dorsal and ventral dentate gyrus through GPER, using the GPER agonist, G1, and antagonist, G15. Ovariectomized adult female rats received a single injection of either: 17β-estradiol (10 μg), G1 (0.

Multiparity-induced enhancement of hippocampal neurogenesis and spatial memory depends on ovarian hormone status in middle age.

Menopause is associated with cognitive decline, and previous parity can increase or delay the trajectory of cognitive aging. Furthermore, parity enables the hippocampus to respond to estrogens in middle age. The present study investigated how previous parity and estrogens influence cognition, neurogenesis, and neuronal activation in response to memory retrieval in the hippocampus of middle-aged females.

Kinetic characterization of hydrolysis of nitrocefin, cefoxitin, and meropenem by β-lactamase from Mycobacterium tuberculosis.

The constitutively expressed, chromosomally encoded β-lactamase (BlaC) is the enzyme responsible for the intrinsic resistance to β-lactam antibiotics in Mycobacterium tuberculosis. Previous studies from this laboratory have shown that the enzyme exhibits an extended-spectrum phenotype, with very high levels of penicillinase and cephalosporinase activity, as well as weak carbapenemase activity [Tremblay, L. W.

Hippocampus-dependent learning influences hippocampal neurogenesis.

The structure of the mammalian hippocampus continues to be modified throughout life by continuous addition of neurons in the dentate gyrus. Although the existence of adult neurogenesis is now widely accepted the function that adult generated granule cells play is a topic of intense debate. Many studies have argued that adult generated neurons, due to unique physiological characteristics, play a unique role in hippocampus-dependent learning and memory.

Sex differences in neurogenesis and activation of new neurons in response to spatial learning and memory.

Adult hippocampal neurogenesis is often associated with hippocampus-dependent learning and memory. Throughout a new neuron's development, it is differentially sensitive to factors that can influence its survival and functionality. Previous research shows that spatial training that occurred 6-10 days after an injection of the DNA synthesis marker, bromodeoxyuridine (BrdU), increased cell survival in male rats.

Effects of delta opioid receptors activation on a response inhibition task in rats.

Rationale: Response inhibition, a primary symptom of many psychiatric disorders, is mediated through a complex neuropharmacological network that involves dopamine, serotonin, glutamate, noradrenaline, and cannabinoid mechanisms. Recently, we identified an opioidergic contribution to response inhibition by showing that deletion of mu or delta opioid receptors in mice alters motor impulsivity.

Objectives: We investigated this phenomenon further by testing whether pharmacological activation of opioid receptors disrupts the ability to inhibit a motor response.