Evaluation of the effects of morphine consumption during lactation period on learning and memory of rat�s offspring

Background and Aim: The frequent use of opioids changes function and plasticity of neural circuits. Exposing the immature nervous system to opioids can have deeper and more extensive impacts. The aim of this study was to investigate the effects of morphine consumption during lactation period on learning and memory of rats offspring. Material and Methods: This experimental study included 40 male Wistar rats with age range of 45-50 days. Animals were divided into control group (CO) and 3 experimental groups of rats whose mothers had received subcutaneous injections of 5 (M5), 10 (M10) or 20 (M20) mg/kg morphine every 12 hours during lactation period. Spatial learning was evaluated by Morris water maze (MWM) on 4 consecutive days (4 trials/day). Spatial memory retrieval was also evaluated on the last day. Results: Our results indicated that the rats whose mothers had received morphine during lactation period spent more time and traveled more distance to find the hidden platform than the controls in the learning stage. These differences were statistically significant when doses of 10 and 20 mg/kg morphine (P<0.001) were used. Also, they spent less time and passed less distance in the target quadrant in probe trial (P<0.001). Conclusion: Morphine consumption during lactation period impairs spatial learning and memory of the rats' offspring in a dose dependent manner. © 2018, Kurdistan University of Medical Sciences. All rights reserved

Behavioral and electrophysiological aspects of cognition in neonate rats lactated by morphine addicted mothers

Objective(s): In addition to genetic factors, environmental phenomena during postnatal age highly affect development and, in turn, function of the brain. The present work evaluates if morphine consumption during lactation period influences the spatial performances and synaptic plasticity in rats at neonatal period of age. Materials and Methods: Three groups of mothers were subcutaneously administered by 5 (M5), 10 (M10) or 20 (M20) mg/kg morphine every 12 hours during the lactation period. At 45 days old, their offspring were introduced to Morris water maze for assessment of spatial learning and memory. Basic field excitatory post-synaptic potentials (fEPSPs) were recorded in the CA1 area of hippocampus and, then, long term potentiation (LTP) was induced by tetanic stimulation. Results: We found that the M10 and M20 rats spent more time and traveled longer distance to find the hidden platform of maze when compared to the control animals (P<0.05 for all comparisons). Similarly, these two morphine-exposed groups were inferior in the memory consolidation compared to their control counterparts. Comparing control and M20 rats revealed that morphine exposure decreases the mean amplitude and slope 10-90 of fEPSPs about 30 percent (P<0.001 for both comparisons) and inhibits the LTP induction in the CA1 area circuits. Conclusion: The present study provides behavioral and electrophysiological proofs for negative effect of morphine on the hippocampal-related function in the neonatally morphine-exposed rats. © 2019, Mashhad University of Medical Sciences. All rights reserved

An Evaluation of the Effect of Deprivation of Maternal Care on LTP Induction in Neurons of Hippocampal CA1 Region in Morphine-Dependent Rats

BACKGROUND AND OBJECTIVE: Deprivation of maternal care as a stressor causes disruption in cognitive and neurochemical activities of the brain. The aim of this study was to evaluation the effect of deprivation of maternal care on LTP induction in neurons of hippocampal CA1 region in morphine-dependent rats. METHODS: This experimental study was conducted among 40 45-day-old male rats in control group, morphine-dependent group, and 3 groups of rats that were deprived of treatment for one, two and three weeks after birth for 3 hours daily. Except for the control group, the rest of the groups received 10 mg/kg body weight morphine sulfate subcutaneously every 12 hours for 10 days. On the eleventh day, the symptoms of deprivation syndrome were investigated by the Gellert-Holtzman method, and on the following day, the synaptic plasticity of neurons in CA1 region was studied. FINDINGS: The Gellert-Holtzman score in the morphine-dependent group was 14.98±4.16 and increased to 31.79±5.12 in the group that was deprived of maternal treatment for 3 weeks (p<0.001). Although morphine dependence did not affect basic responses of CA1 region neurons and LTP induction, deprivation of maternal care reduced the range of basic responses from 1.01±0.04 in the morphine-dependent group to 0.68±0.09 mV in the group that was deprived of maternal care for 3 weeks (p<0.001) and prevented LTP induction (p<0.001) in a time-dependent manner. CONCLUSION: The results of the study showed that deprivation of maternal care undermines the postsynaptic potential of the hippocampal CA1 region following morphine administration and disrupts the synaptic plasticity of the neurons in this region

Eavaluation of antinociceptic effect of nano-emulsion gel conataining rosemary and peppermint essential oils in a rat model of osteoarthritis

Background and Aim: Despite identification of the antinociceptive effects of rosemary and peppermint essential oils, use of these essential oils has been limited due to its low solubility in water and low bioavailability. Use of nanoparticles is one of the ways to overcome these limitations. The aim of this study was to evaluate the antinociceptive effect of nano-emulsions containing rosemary and peppermint essential oils in an animal model of osteoarthritis (OA). Materials and Methods: In this experimental study nano-emulsions containing rosemary and peppermint essential oils were prepared by spontaneous emulsification. In order to investigate the analgesic effect, 30 male rats were randomly assigned to 5 groups: sham (receiving saline injection into the knee), osteoarthritis(receiving intra-articular injection of 2 mg monosodiumiodoacetate), OA (receiving gels containing nano-emulsion, or rosemary and peppermint essential oil or diclofenac sodium). Treatments were administered topically at a dose of 1 ml daily. Mechanical and thermal allodynia and thermal hyperalgesia tests were performed on the 1 st , 4 th , 7 th and 14 th days after injection. Data were analyzed by repeated measures ANOVA. Results: OA group showed a significant increased behavioral response to the mechanical and thermal stimuli on all days of the experiment compared to the control group (P&lt;0.001). Use of nano-emulsion or diclofenac gel led to significant increase in the response threshold to von-Frey fillamets (P&lt;0.001), decreased response to acetone (P&lt;0.05), and increased paw withdrawal latency (P&lt;0.05). Histopathology of knee tissues confirmed the results of behavioral tests. Conclusion: Nano-emulsion containing essential oils of rosemary and peppermint reduced pain of osteoarthritis in rats. The nano-emulsification process seems to enhance the antinociceptive effect of rosemary and peppermint essential oils. © 2018, Kurdistan University of Medical Sciences. All rights reserved

Dairy consumption and cardiometabolic diseases: systematic review and updated meta-analyses of prospective cohort studies

Purpose of Review Dairy products contain both beneficial and harmful nutrients in relation to cardiometabolic diseases. Here, we provide the latest scientific evidence regarding the relationship between dairy products and cardiometabolic diseases by reviewing the literature and updating meta-analyses of observational studies. Recent Findings We updated our previous meta-analyses of cohort studies on type 2 diabetes, coronary heart disease (CHD), and stroke with nine studies and confirmed previous results. Total dairy and low-fat dairy (per 200 g/d) were inversely associated with a 3–4% lower risk of diabetes. Yogurt was non-linearly inversely associatedwith diabetes (RR = 0.86, 95%CI: 0.83–0.90 at 80 g/ d). Total dairy and milk were not associated with CHD (RR~1.0). An increment of 200 g of daily milk intake was associated with an 8% lower risk of stroke. Summary The latest scientific evidence confirmed neutral or beneficial associations between dairy products and risk of cardiometabolic diseases

Evaluation of the effect of MbNPV on cabbage moth, Plutella xylostella (Lep.: Plutellidae), in laboratory conditions

Cabbage moth, Plutella xylostella L., is the most important pest in cabbage and canola cultures in Iran. Nuclear polyhedrosis viruses are known as important natural enemies of this pest. Because of economic importance of cabbage moth and the necessity of its control, MbNPV (Baculoviridae) was chosen to evaluate its effect on cabbage moth. Experimental data showed that the virus had high virulence and could be considered as the important agent for the control of this insect. In infestation of egg surfaces with 1 Ã 105 PIB/ml of MbNPV, all of larvae died three days after hatching. The LC50 value for the second instar larvae of cabbage moth was calculated 11.99 PIB/mm2. The LT50 values for the same larvae with 19.5 and 47.86 PIB/mm2 doses of MbNPV were 7.16 and 6.11 days, respectively. Mean percentages of mortality with 47.86 PIB/mm2 for 2nd, 3rd and 4th instar larvae were 74.44, 42.78 and 11.11, respectively

Prenatal urban traffic noise exposure impairs spatial learning and memory and reduces glucocorticoid receptor expression in the hippocampus of male rat offspring

Introduction: Exposure to noise stress during early life may permanently affect the structure and function of the central nervous system. The aim of this study was to evaluate the effects of prenatal exposure to urban traffic noise on the spatial learning and memory of the rats' offspring and the expression of glucocorticoid receptors (GRs) in their hippocampi. Methods: Three g\roups of pregnant rats were exposed to recorded urban traffic noise for 1, 2 or 4 h/day during the last week of pregnancy. At the age of 45 days, their male offspring were introduced to the Morris water maze (MWM) for assessment of spatial learning and memory. The corticosterone levels were measured in the offspring's sera by radioimmunoassay, and the relative expression of glucocorticoid and mineralocorticoid receptors (MRs) in their hippocampi was evaluated via RT-PCR. Results: Facing urban traffic noise for 2 and 4 h/day during the third trimester of pregnancy caused the offspring to spend more time and to travel a larger distance than the controls to find the target platform. Analogously, these two groups were inferior to their control counterparts in the probe test. Also, prenatal noise stress elevated the corticosterone concentration in the sera of the rats' offspring and dose-dependently decreased the relative expression of the mRNA of both GRs and MRs in their hippocampi. Conclusions: Urban traffic noise exposure during the last trimester of pregnancy impairs spatial learning and memory of rat offspring and reduces GRs and MRs gene expression in the hippocampus

Prenatal urban traffic noise exposure impairs spatial learning and memory and reduces glucocorticoid receptor expression in the hippocampus of male rat offspring

Introduction: Exposure to noise stress during early life may permanently affect the structure and function of the central nervous system. The aim of this study was to evaluate the effects of prenatal exposure to urban traffic noise on the spatial learning and memory of the rats' offspring and the expression of glucocorticoid receptors (GRs) in their hippocampi. Methods: Three g\roups of pregnant rats were exposed to recorded urban traffic noise for 1, 2 or 4 h/day during the last week of pregnancy. At the age of 45 days, their male offspring were introduced to the Morris water maze (MWM) for assessment of spatial learning and memory. The corticosterone levels were measured in the offspring's sera by radioimmunoassay, and the relative expression of glucocorticoid and mineralocorticoid receptors (MRs) in their hippocampi was evaluated via RT-PCR. Results: Facing urban traffic noise for 2 and 4 h/day during the third trimester of pregnancy caused the offspring to spend more time and to travel a larger distance than the controls to find the target platform. Analogously, these two groups were inferior to their control counterparts in the probe test. Also, prenatal noise stress elevated the corticosterone concentration in the sera of the rats' offspring and dose-dependently decreased the relative expression of the mRNA of both GRs and MRs in their hippocampi. Conclusions: Urban traffic noise exposure during the last trimester of pregnancy impairs spatial learning and memory of rat offspring and reduces GRs and MRs gene expression in the hippocampus