Hormones and behavior
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Hormones and behavior · Sep 2013
Sex differences in oxytocin receptor binding in forebrain regions: correlations with social interest in brain region- and sex- specific ways.
Social interest reflects the motivation to approach a conspecific for the assessment of social cues and is measured in rats by the amount of time spent investigating conspecifics. Virgin female rats show lower social interest towards unfamiliar juvenile conspecifics than virgin male rats. We hypothesized that the neuropeptide oxytocin (OT) may modulate sex differences in social interest because of the involvement of OT in pro-social behaviors. ⋯ Proestrus/estrus females showed similar social interest to non-estrus females despite increased OTR binding densities in several forebrain areas. Maternal experience had no immediate or long-lasting effects on social interest or OT brain parameters except for higher OTR binding in the medial amygdala in primiparous females. Together, these findings demonstrate that there are robust sex differences in OTR binding densities in multiple forebrain regions of rats and that OTR binding densities correlate with social interest in brain region- and sex-specific ways.
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Hormones and behavior · Aug 2013
Progesterone and vitamin D: Improvement after traumatic brain injury in middle-aged rats.
Progesterone (PROG) and vitamin D hormone (VDH) have both shown promise in treating traumatic brain injury (TBI). Both modulate apoptosis, inflammation, oxidative stress, and excitotoxicity. We investigated whether 21 days of VDH deficiency would alter cognitive behavior after TBI and whether combined PROG and VDH would improve behavioral and morphological outcomes more than either hormone alone in VDH-deficient middle-aged rats given bilateral contusions of the medial frontal cortex. ⋯ Combination therapy showed moderate improvement in preserving spatial and reference memory but was not significantly better than PROG monotherapy. However, combination therapy significantly reduced neuronal loss and the proliferation of reactive astrocytes, and showed better efficacy compared to VDH or PROG alone in preventing MAP-2 degradation. VDH+PROG combination therapy may attenuate some of the potential long-term, subtle, pathophysiological consequences of brain injury in older subjects.
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Hormones and behavior · Jul 2013
ReviewThe development of psychotic disorders in adolescence: a potential role for hormones.
This article is part of a Special Issue "Puberty and Adolescence". The notion that adolescence is characterized by dramatic changes in behavior, and often by emotional upheaval, is widespread and longstanding in popular western culture. In recent decades, this notion has gained increasing support from empirical research showing that the peri- and post-pubertal developmental stages are associated with a significant rise in the rate of psychiatric symptoms and syndromes. ⋯ In this paper, we begin by providing an overview of the nature and course of psychotic disorders during adolescence/young adulthood. We then turn to the role of hormones in modulating normal brain development, and the potential role they might play in the abnormal brain changes that characterize youth at clinical high-risk (CHR) for psychosis. The activational and organizational effects of hormones are explored, with a focus on how hormone-induced changes might be linked with neuropathological processes in the emergence of psychosis.
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Hormones and behavior · Jul 2013
ReviewChanges in hypothalamic-pituitary-adrenal stress responsiveness before and after puberty in rats.
This article is part of a Special Issue "Puberty and Adolescence". Many endocrine changes are associated with pubertal and adolescent development. One such change is the responsiveness of the hypothalamic-pituitary-adrenal (HPA) axis to physical and/or psychological stressors. ⋯ Specifically, exposure to various stressors results in greater adrenocorticotropic hormone (ACTH) and glucocorticoid responses in peripubertal compared to adult animals. This review will focus on how stress reactivity changes throughout puberty and adolescence, as well as potential mechanisms that mediate these changes in stress responsiveness. Though the implications of these pubertal shifts in stress responsiveness are not fully understood, the significant increase in stress-related mental and physical dysfunctions during this stage of development highlights the importance of studying pubertal and adolescent maturation of HPA function and its reactivity to stress.
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Hormones and behavior · Feb 2013
Estradiol reduces depressive-like behavior through inhibiting nitric oxide/cyclic GMP pathway in ovariectomized mice.
Estradiol decline has been associated with depressive-like behavior in female mice and NO has been suggested to play a major role in the pathogenesis of major depression. This study was conducted to investigate the antidepressant-like effects of acute estradiol administration in female ovariectomized (OVX) mice and the possible role of nitric oxide (NO)/cyclic GMP (cGMP) pathway. To this end, bilateral ovariectomy was performed in female mice and different doses of estradiol were injected alone or in combination with non-specific NO synthase (NOS) inhibitor (L-NAME), selective neural NOS (nNOS) inhibitor (7-NI), an NO precursor (L-arginine) or selective phosphodiesterase type 5 inhibitor (sildenafil). ⋯ Also a sub-effective dose of 7-NI (25 mg/kg), 30 min after a sub-effective dose of estradiol (1 μg/kg, s.c.) showed antidepressant-like effect in OVX mice. Both the NO precursor L-arginine (750 mg/kg, i.p.) and the cGMP-specific phosphodiesterase type 5 inhibitor sildenafil (5 mg/kg, i.p.), 30 min before estradiol treatment, prevented the antidepressant-like effect of a potent dose of estradiol (10 μg/kg, s.c.) in OVX mice. The present findings suggest that suppression of the NO synthase/NO/cGMP pathway may be involved in the antidepressant-like effects of estradiol in OVX mice.