Repeated forced swim stress has additive effects in anxiety behavior and in cathecolamine levels of adult rats exposed to deltamethrin

Boophone disticha attenuates five day repeated forced swim-induced stress and adult hippocampal neurogenesis impairment in male Balb/c mice

Depression is one of the most common neuropsychiatric disorders and is associated with dysfunction of the neuroendocrine system and alterations in specific brain proteins. Boophone disticha (BD) is an indigenous psychoactive bulb that belongs to the Amaryllidacae family, which is widely used in Southern Africa to treat depression, with scientific evidence of potent antidepressant-like effects. The present study examined the antidepressant effects of BD and its mechanisms of action by measuring some behavioural parameters in the elevated plus maze, brain content of corticosterone, brain derived neurotropic factor (BDNF), and neuroblast differentiation in the hippocampus of Balb/c mice exposed to the five day repeated forced swim stress (5d-RFSS). Male Balb/c mice were subjected to the 5d-RFSS protocol to induce depressive-like behaviour (decreased swimming, increased floating, decreased open arm entry, decreased time spent in the open arms and decreased head dips in the elevated plus maze test) and treated with distilled water, fluoxetine and BD. BD treatment (10 mg/kg/p.o for 3 weeks) significantly attenuated the 5d-RFSS-induced behavioural abnormalities and the elevated serum corticosterone levels observed in stressed mice. Additionally, 5d-RFSS exposure significantly decreased the number of neuroblasts in the hippocampus and BDNF levels in the brain of Balb/c mice, while fluoxetine and BD treatment attenuated these changes. The antidepressant effects of BD were comparable to those of fluoxetine, but unlike fluoxetine, BD did not show any anxiogenic effects, suggesting better pharmacological functions. In conclusion, our study shows that BD exerted antidepressant-like effects in 5d-RFSS mice, mediated in part by normalizing brain corticosterone and BDNF levels.

Motor, memory, and anxiety-like behavioral impairments associated with brain-derived neurotrophic factor and dopaminergic imbalance after inhalational exposure to deltamethrin

Believed to cause damage to the nervous system and possibly being associated with neurodegenerative diseases, deltamethrin (DM) is a type II pyrethroid used in pest control, public health, home environment, and vector control. The objective of this study was to evaluate the motor, cognitive and emotional changes associated with dopaminergic and BDNF imbalance after DM exposure in rats. Sixty Wistar rats (9-10 months-old) were used, under Ethics Committee on Animal Research license (ID 19/2017). The animals were randomly divided into four groups: control (CTL, 0.9% saline), DM2 (2mg DM in 1.6mL 0.9% saline), DM4 (4mg of DM in 1.6mL of 0.9% saline), and DM8 (8mg of DM in 1.6mL of 0.9% saline). DM groups were submitted to 9 or 15 inhalations, one every 48hours. Half of the animals from each group were randomly selected and perfused 24hours after the 9th or 15th inhalation. Throughout the experiment, the animal's behavior were evaluated using catalepsy test, open field, hole-board test, Modified Elevated Plus Maze, and social interaction. At the end of the experiments, the rats were perfused transcardially and their brains were processed for Tyrosine Hydroxylase (TH) and Brain derived neurotrophic factor (BDNF) immunohistochemistries. The animals submitted to 9 inhalations of DM showed a reduction in immunoreactivity for TH in the Substantia nigra pars compacta (SNpc), ventral tegmental area (VTA), and dorsal striatum (DS) areas, and an increase in BDNF in the DS and CA1, CA3 and dentate gyrus (DG) hippocampal areas. Conversely, the animals submitted to 15 inhalations of DM showed immunoreactivity reduced for TH in the SNpc and VTA, and an increase in BDNF in the hippocampal areas (CA3 and DG). Our results indicate that the DM inhalation at different periods induce motor and cognitive impairments in rats. Such alterations were accompanied by dopaminergic system damage and a possible dysfunction on synaptic plasticity.

Exploring the impact of trauma type and extent of exposure on posttraumatic alterations in 5-HT1A expression

The long-term behavioral, psychological, and neurobiological effects of exposure to potentially traumatic events vary within the human population. Studies conducted on trauma-exposed human subjects suggest that differences in trauma type and extent of exposure combine to affect development, maintenance, and treatment of a variety of psychiatric syndromes. The serotonin 1-A receptor (5-HT1A) is an inhibitory G protein-coupled serotonin receptor encoded by the HTR1A gene that plays a role in regulating serotonin release, physiological stress responding, and emotional behavior. Studies from the preclinical and human literature suggest that dysfunctional expression of 5-HT1A is associated with a multitude of psychiatric symptoms commonly seen in trauma-exposed individuals. Here, we synthesize the literature, including numerous preclinical studies, examining differences in alterations in 5-HT1A expression following trauma exposure. Collectively, these findings suggest that the impact of trauma exposure on 5-HT1A expression is dependent, in part, on trauma type and extent of exposure. Furthermore, preclinical and human studies suggest that this observation likely applies to additional molecular targets and may help explain variation in trauma-induced changes in behavior and treatment responsivity. In order to understand the neurobiological impact of trauma, including the impact on 5-HT1A expression, it is crucial to consider both trauma type and extent of exposure.

A pilot trial of metformin for insulin resistance and mood disturbances in adolescent and adult women with polycystic ovary syndrome

We examine the effects of metformin on insulin resistance (IR) and mood including in adolescent and adult women with polycystic ovary syndrome (PCOS). This trial was conducted in 19 adolescents (age ≤18 years) and 25 adult (age >18 years) women with PCOS. Anthropometric and measurements including, serum glucose, endocrine panel, and lipid profile were performed at baseline. IR was measured by Homeostasis Model Assessment IR (HOMA-IR). Anxiety and depression were measured by Beck's Anxiety (BAI) and Depression Inventories (BDI-II). All tests were repeated after a 90-day treatment with metformin (1,500 mg/day). The severity of depression and anxiety decreased after 90-day treatment with metformin in women diagnosed with PCOS. The BAI scores were higher in adolescent group while BDI-II scores were higher in the adult group (p = .016). After 90-day metformin treatment, both BDI-II and BAI scores were decreased by 3.3 and 3.4, respectively (p < .001). Indicators of IR and obesity were improved with this therapy. Although the adolescents weighed lower than the adults, baseline HOMA-IR 5.5 ± 1.7 was higher in this group than 4.4 ± 1.2 in the adult women (p =.022). The findings suggest that metformin decrease IR and improve mood both in adolescent and adult women with PCOS.

Influences of combined traffic noise on anxiety in mice

With the rapid development of traffic facilities in China, traffic noise pollution is increasingly prominent. This research aims to explore the influences of combined traffic noise on receptors' anxiety. Institute of cancer research mice were exposed to combined traffic noise (CTN) from highway and high-speed railway for 52days, whose day-night equivalent continuous A-weighted sound pressure level (L_dn) was 70dB(A). The impacts of CTN on anxiety were explored by behavior tests and monoamine neurotransmitter assays. The results were in depth discussed in comparison to two previous studies on the impacts of single high-speed railway noise (HSRN) and aircraft noise (AN), but data from the three studies were not merged and statistically compared. No significant differences were shown in the behavioral indicators and the monoamine levels between the experimental and control groups after CTN exposure, indicating no obvious impacts of 70dB(A) CTN on anxiety in mice were found in this study. When L_dn was approximately 70dB(A), CTN had less obvious impacts on anxiety than HSRN and AN, which is mainly related to that both the acoustical parameters of noise events [maximum noise level (L_Amax), noise events duration, slope of rise, difference of L_Amax from 1-min background equivalent continuous A-weighted sound pressure level] and modified day-night equivalent continuous R-weighted sound pressure level (considering animal auditory sensitivity to different sound frequencies and circadian rhythms) of CTN are smaller than those of HSRN and AN.

Brain cholinergic alterations in rats subjected to repeated immobilization or forced swim stress on lambda-cyhalothrin exposure

Role of immobilization stress (IMS), a psychological stressor and forced swim stress (FSS), a physical stressor was investigated on the neurobehavioral toxicity of lambda-cyhalothrin (LCT), a new generation type-II synthetic pyrethroid. Pre-exposure of rats to IMS (15 min/day) or FSS (3 min/day) for 28 days on LCT (3.0 mg/kg body weight, p.o.) treatment for 3 days resulted to decrease spatial learning and memory and muscle strength associated with cholinergic-muscarinic receptors in frontal cortex and hippocampus as compared to those exposed to IMS or FSS or LCT alone. Decrease in acetylcholinesterase activity, protein expression of ChAT and PKC-β1 associated with decreased mRNA expression of CHRM2, AChE and ChAT in frontal cortex and hippocampus was also evident in rats pre-exposed to IMS or FSS on LCT treatment, compared to rats exposed to IMS or FSS or LCT alone. Interestingly, changes both in behavioral and neurochemical endpoints were marginal in rats subjected to IMS or FSS for 28 days or those exposed to LCT for 3 days alone, compared to controls. The results suggest that stress is an important contributor in LCT induced cholinergic deficits.