Combination of low doses of mirtazapine plus venlafaxine produces antidepressant-like effects in rats, without affecting male or female sexual behavior.

Rationale: Pharmacological treatments for depression are not always effective and produce unwanted side effects. Male and female sexual dysfunction is one of these side effects, which can lead to treatment withdrawal. Combination of two antidepressants with different mechanisms of action, like mirtazapine (MTZ) and venlafaxine (VLF) have been shown to be effective for treatment-resistant depression in humans.

Diabetes mellitus and female sexual response: what do animal models tell us?

Background: One of the less explored effects of diabetes mellitus (DM) is female sexual dysfunction. Females of different species have been used as models.

Aim: To analyze the information of animal models of DM and female sexual response (FSR).

Chronic moderate hyperglycemia does not alter sexual motivation in the female rat.

The relationship between diabetes mellitus type 2 (DM2) and sexual desire in women has not been systematically studied, therefore, animal models have been used for this purpose. When streptozotocin (STZ) is administered in the neonatal stage, the rat shows moderate chronic hyperglycemia and glucose intolerance in adulthood, resembling a DM2 model. These females show less alterations of sexual behavior (a slight decreased proceptivity and loss of paced mating) than their counterpart with severe hyperglycemia.

Estradiol modulates the role of the spinal α-subunit containing GABA receptors in female rats with neuropathic pain.

The purpose of this study was to investigate the mechanisms underlying sex differences in the role of spinal α-subunit containing GABA (αGABA) receptors in rats with neuropathic pain. Intrathecal 2,5-dihydro-7-methoxy-2-(4-methoxyphenyl)-3H-pyrazolo [4,3-c] quinoline-3-one (PZ-II-029, positive allosteric modulator of αGABA receptors) reduced tactile allodynia in female but not in male rats with neuropathic pain. PZ-II-029 was also more effective in females than males in inflammatory and nociplastic pain.

Multiparity favors same-sex partner preference in male rats.

Same-sex partner preference is present in many mammals, including rodents. Several possible causal factors have been proposed for the establishment of this preference. The Fraternal Birth Order effect refers to the observation that older brothers increase the probability of homosexuality in men, but no experiment has analyzed this possibility.

Spinal alarmin HMGB1 and the activation of TLR4 lead to chronic stress-induced nociceptive hypersensitivity in rodents.

Chronic stress affects millions of people around the world, and it can trigger different behavioral disorders like nociceptive hypersensitivity and anxiety, among others. However, the mechanisms underlaying these chronic stress-induced behavioral disorders have not been yet elucidated. This study was designed to understand the role of high-mobility group box-1 (HMGB1) and toll-like receptor 4 (TLR4) in chronic stress-induced nociceptive hypersensitivity.

Distribution of estrogen receptors alpha and beta in the brain of male rats with same-sex preference.

Two distinct estrogen receptors (ERs) exist, ERα and ERβ. Both receptors participate in sexual differentiation of the rat brain and likely participate in the regulation of adult sexual orientation (i.e.

Androgen receptors immunoreactivity in the rat brain of males with same-sex preference.

Androgen receptors (AR) are crucial in the control of male sexual behavior and sex preference. AR are particularly concentrated in areas related with the neuroendocrine control of sex preference including the medial amygdala (MeA), the ventromedial nucleus of the hypothalamus (VMH), the bed nucleus of the stria terminalis (BNST), the medial preoptic area (MPOA), the nucleus accumbens (Acb), the suprachiasmatic (SCh) and supraoptic (SO) nuclei, but also seem to be important for the control of reproductive processes in the hippocampus (CA1-CA4 and dentate gyrus, DG). In the present study we analyzed the density of AR in these brain areas of adult male rats with sexual preference (established in a three-compartment box).

Pharmacological Interaction of Quercetin Derivatives of and Clinical Drugs in Experimental Fibromyalgia.

Fibromyalgia (FM) is a pain syndrome characterized by chronic widespread pain and CNS comorbidities. var. is a medicinal species used to treat anxiety, insomnia, and acute or chronic pain.

Retracted: Sexual orientation, neuropsychiatric disorders and the neurotransmitters involved.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).

Reduced sexual motivation of diabetic female rats: Restoration with insulin.

The aim of this study was to evaluate female rat sexual motivation in a model of diabetes mellitus type 1. Severe hyperglycemia was induced in ovariectomized Wistar rats by injecting streptozotocin [STZ, 100 mg/kg, i.p.

Lack of interaction between prenatal stress and prenatal letrozole to induce same-sex preference in male rats.

Same-sex partner preference between males has been observed in all species in which this behavior has been studied. Disruption of brain estradiol synthesis during development has been proposed as one of the biological causes underlying this behavior in some mammals. In support of this possibility, perinatal administration of aromatase inhibitors (such as letrozole) to male rat pups, induces around half of them to have same-sex preference and female sexual behavior in adulthood.

The combination of mirtazapine plus venlafaxine reduces immobility in the forced swim test and does not inhibit female sexual behavior.

Introduction: Depression is a psychiatric disorder with higher incidence in women. Among the most common and less investigated adverse effects of antidepressants are the female sexual dysfunctions. Up to one third of the patients fail to respond to antidepressants; therefore, more treatment alternatives are necessary.

Does Chronic Hyperglycemia Affect Female Rat Sexual Behavior? Differences in Paced and Non-Paced Mating.

Introduction: Diabetes mellitus has been associated with sexual dysfunction; however, in women this relationship is controversial. A study using a model of type 2 diabetes mellitus (DM2) failed to find a reduced receptivity in the non-paced mating (NPM), but the appetitive aspects of female sexual behavior have not been evaluated, for example, in the paced mating (PM) paradigm.

Aim: To evaluate all components of female sexual behavior (in NPM and PM) in a model of DM2 using ovariectomized (OVX) (treated with steroids) or intact female rats (non-OVX) in natural proestrus.

Establishment of partner preference in male rats: Effect of prenatal letrozole and sexual experience.

Repeated testing for masculine sexual behavior influences female sex preference in males. Males perinatally treated with aromatase inhibitors show male preference, but also copulate with the receptive female. Such copulation modifies sex preference most likely because of its rewarding properties.

Observing Erotic Videos With Heterosexual Content Induces Different Cerebral Responses in Homosexual and Heterosexual Men.

To determine the cerebral functionality associated with the perception and processing of erotic stimuli in men with different sexual orientation, this work evaluated the electroencephalographic activity (EEG) from several cortical areas, as well as subjective arousal in homosexual and heterosexual men during observation of an erotic film with heterosexual content. The heterosexual men rated the erotic video with higher general and sexual arousal than the homosexual participants. During observation of the neutral and erotic videos, both groups showed a decreased amplitude of the alpha band in prefrontal and parietal cortices, indicating increased attention.

Influence of sex and estrous cycle on blood glucose levels, body weight gain, and depressive-like behavior in streptozotocin-induced diabetic rats.

Depression is the most common psychiatric disorder in diabetic patients, showing higher rates in women than in men. This comorbidity has been studied in rodents using the streptozotocin (STZ)-induced diabetes (DM) model, consistently reporting a depressive-like profile in males. Few articles have examined these disturbances in females (ovariectomized or combined with male rats) yielding controversial results.

Male rats with same-sex preference show higher immobility in the forced swim test, but similar effects of fluoxetine and desipramine than males that prefer females.

Sex preference in male rats is partly determined by the organizational action of estradiol. Thus, several paradigms have used aromatase inhibitors to manipulate sex preference. We recently showed that a subpopulation of male rats prenatally treated with letrozole (0.

Neuropeptide and steroid hormone mediators of neuroendocrine regulation.

To maintain the health and well-being of all mammals, numerous aspects of physiology are controlled by neuroendocrine mechanisms. These mechanisms ultimately enable communication between neurones and glands throughout the body and are centrally mediated by neuropeptides and/or steroid hormones. A recent session at the International Workshop in Neuroendocrinology highlighted the essential roles of some of these neuropeptide and steroid hormone mediators in the neuroendocrine regulation of stress-, reproduction- and behaviour-related processes.

Sleep architecture is altered in the reserpine-induced fibromyalgia model in ovariectomized rats.

Fibromyalgia (FM) is a musculoskeletal chronic pain syndrome with various concomitant symptoms like sleep disorders. FM patients are mainly women and menopause might play an important role in the altered processing of somatosensory information. Adverse effects and moderated efficacy of drugs promote treatment discontinuation by patients.

Reduced Lordosis and Enhanced Aggression in Paced and Non-Paced Mating in Diabetic Female Rats.

Background: Clinical studies have shown altered sexual function in people with diabetes; basic science studies, using the streptozotocin (STZ)-induced animal model of type 1 diabetes mellitus (DM1), have consistently reported decreased sexual behavior in hyperglycemic female animals, but features of sexual motivation and aggressive behavior have not been explored in these animals.

Aim: To study several parameters that denote sexual motivation in STZ-treated female rats and to compare behavioral features of sexual behavior and aggression in non-paced mating (NPM) and paced mating (PM) conditions.

Methods: DM1 was induced by injecting STZ (diluted in citrate buffer) at a dose of 50 mg/kg intraperitoneally over 2 consecutive days into ovariectomized Wistar rats.

Sex differences and estradiol involvement in hyperalgesia and allodynia in an experimental model of fibromyalgia.

Fibromyalgia (FM) is a musculoskeletal chronic pain syndrome. Its prevalence in women is higher than in men possibly by hormonal factors given that symptoms are aggravated during sex hormone-related events, such as the premenstrual period, pregnancy, postpartum or menopause. The aim of the present study was to investigate whether hyperalgesia and allodynia, in reserpine-induced experimental FM, depend on sex, estrous cycle, ovariectomy and replacement with 17β-estradiol.

Hormones and the Coolidge effect.

The Coolidge effect is the renewal of sexual behavior after the presentation of a novel sexual partner and possibly occurs as the result of habituation and dishabituation processes. This re-motivation to copulate is well studied in males and is commonly related to sexual satiety, which involves several neurobiological changes in steroid receptors and their mRNA expression in the CNS. On the other hand, there are few reports studying sexual novelty in females and have been limited to behavioral aspects.

The anxiolytic-like effect of rutin in rats involves GABAA receptors in the basolateral amygdala.

Rutin is a bioflavonoid found in medicinal plants used to reduce anxiety. Evidence is lacking of rutin's anxiolytic-like activity, putative mechanism(s) of action, and neural sites of effects. The basolateral amygdala (BLA) is the main brain region that regulates anxiety, through GABAA/benzodiazepine (BDZ) receptors, which are modulated by flavonoids.

Prenatal administration of letrozole reduces SDN and SCN volume and cell number independent of partner preference in the male rat.

During development, the exposure to testosterone, and its conversion to estradiol by an enzyme complex termed aromatase, appears to be essential in adult male rats for the expression of typical male sexual behavior and female-sex preference. Some hypothalamic areas are the supposed neural bases of sexual preference/orientation; for example, male-oriented rams have a reduced volume of the sexually dimorphic nucleus (oSDN), while in homosexual men this nucleus does not differ from that of heterosexual men. In contrast, homosexual men showed a larger number of vasopressinergic cells in the suprachiasmatic nucleus (SCN).