Social separation and diazepam withdrawal increase anxiety in the elevated plus-maze and serotonin turnover in the median raphe and hippocampus

2009 ◽  
Vol 24 (5) ◽  
pp. 725-731 ◽  
Author(s):  
Lucinéia dos Santos ◽  
Telma GCS de Andrade ◽  
Frederico G Graeff
2020 ◽  
Vol 34 (8) ◽  
pp. 901-913
Author(s):  
Willian Lazarini-Lopes ◽  
Fabiana Corsi-Zuelli ◽  
Cláudia M Padovan

Background: Exposure to stressful aversive situations induces physiological and behavioral changes. Serotonin has been suggested to mediate such changes, as well as adaptation to stressful events. Serotoninergic projections arising from the median raphe nucleus to the dorsal hippocampus have been suggested to promote adaptation to chronic aversive stimuli. Such pathway may involve serotonin type 1a receptor-mediated neurotransmission. However, the serotonin 7 receptor can also be found in the median raphe nucleus and may be involved in mechanisms underlying response to stress. Aims: In this work we sought to investigate if activation of serotonin type 7 receptors would attenuate stress-induced deficits in different animal models of depression. Methods: Male Wistar rats with a guide-cannula aimed to the median raphe nucleus were submitted to restraint or forced swim stress and were tested in an elevated plus maze or forced swim test, respectively, 24 h later. SB 258741 (serotonin type 7 receptor antagonist) and/or LP 44 (serotonin type 7 receptor agonist) were administered intra-median raphe nucleus immediately before or after exposure to stress or before test. Control groups received intra-median raphe nucleus treatment 24 h or immediately before test in the elevated plus maze or forced swim test. Results: LP 44 attenuated restraint-induced exploratory deficits independently of the moment it was administered. Similar results were observed in the forced swim test, with the exception on post-stress condition. These effects on adaptation to stress induced by serotonin type 7 receptor activation were prevented by previous treatment with SB 258741. Conclusions: Our data support the idea that activation of median raphe nucleus serotonin 7 receptor is important to the development of adaptation to stress.


1997 ◽  
Vol 130 (3) ◽  
pp. 228-234 ◽  
Author(s):  
Nick Andrews ◽  
S. E. File ◽  
Cathy Fernandes ◽  
Luis E. Gonzalez ◽  
Nicholas M. Barnes

Planta Medica ◽  
2010 ◽  
Vol 76 (12) ◽  
Author(s):  
C Sampath ◽  
M Holbik ◽  
L Krenn ◽  
V Butterweck

2020 ◽  
Vol 26 (31) ◽  
pp. 3895-3904
Author(s):  
João R.C. Araújo ◽  
Adriana R. Campos ◽  
Marina de Barros M.V. Damasceno ◽  
Sacha A.A.R. Santos ◽  
Maria K.A. Ferreira ◽  
...  

Background: Plant lectins have shown promising biological activities in the central nervous system (CNS). Objective: This study evaluated the effect of DAL, a lectin isolated from the seeds of the Dioclea altissima species, having binding affinity to D-glucose or D-mannose residues, on mice behavior. Methods: Mice (n=6/group) were treated (i.p.) with DAL (0.25, 0.5 or 1 mg/kg) or vehicle and subjected to several tests (open field/OFT, marble-burying/MBT, hole-board/HBT, elevated plus maze/PMT, tail suspension/ TST, forced swimming/FST or rotarod/RRT). Pizotifen, cyproheptadine, flumazenil, L-NAME, 7-NI, Larginine or yohimbine were administered 15 min before DAL (0.5 mg/kg) and the animals were evaluated on PMT. It was also verified whether the DAL effect depended on its structural integrity and ability to interact with carbohydrates. Results: The results showed there were no neurobehavioral changes in the mice at the RRT, FST and locomotion in the OFT. DAL (0.25, 0.5 or 1 mg/kg) increased the behavior of grooming and rearing in the OFT, head dips in the HBT, pedalling in the TST and decreased the number of marbles hidden in the MBT. In the PMT, DAL (0.25, 0.5 and 1 mg/kg) and Diazepam increased the frequency of entries in the open arms and the time of permanence in the open arms without affecting the locomotor activity. The effect of DAL was dependent on carbohydrate interaction and protein structure integrity and it prevented by pizotifen, cyproheptadine, flumazenil, L-NAME and 7-NI, but not by L-arginine or yohimbine. Conclusion: DAL was found to have an anxiolytic-like effect mediated by the 5-HT and GABAergic receptors and NO pathway.


2020 ◽  
Vol 14 (1) ◽  
pp. 36-51 ◽  
Author(s):  
George L. da Silva Oliveira ◽  
José C. Correia L. da Silva ◽  
Ana P. dos Santos C. L da Silva ◽  
Chistiane M. Feitosa ◽  
Fernanda R. de Castro Almeida

Background: Central nervous system disorders such as anxiety, depression and epilepsy are characterized by sharing several molecular mechanisms in common and the involvement of the L-arginine/NO pathway in neurobehavioral studies with β-caryophyllene is still little discussed. Objectives: One of the objectives of the present study was to demonstrate the anxiolytic behavioral effect of β-caryophyllene (β-CBP) in female Swiss mice, as well as to investigate the molecular mechanisms underlying the results obtained. Methods: This study evaluated the neurobehavioral effects of β-CBP using the open field test, rota-rod test, elevated plus maze test, novelty suppressed feeding test, tail suspension test and forced swim test, as well as pilocarpine, pentylenetetrazole and isoniazid-induced epileptic seizure models. Results:: The results demonstrated that the neuropharmacological activities of β-CBP may involve benzodiazepine/GABAergic receptors, since the pre-treatment of β-CBP (200 mg/kg) associated with flumazenil (5 mg/kg, benzodiazepine receptor antagonist) and bicuculline (1 mg/kg, selective GABAA receptor antagonist) reestablished the anxiety parameters in the elevated plus-maze test, as well as the results of reduced latency to consume food in the novelty suppressed feeding test. In addition to benzodiazepine/GABAergic receptors, the neuropharmacological properties of β-CBP may be related to inhibition of nitric oxide synthesis, since pre-treatment with L-arginine (500- 750 mg/kg) reversed significantly the anxiolytic, antidepressant and anticonvulsant activities of β-CBP. Conclusion: The results obtained provide additional support in understanding the neuromolecular mechanisms underlying the anxiolytic, antidepressant and anticonvulsive properties of β-CBP in female Swiss mice.


Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2341
Author(s):  
Conner W. Wallace ◽  
Nari S. Beatty ◽  
Sarah A. Hutcherson ◽  
Heather A. Emmons ◽  
Madison C. Loudermilt ◽  
...  

Diet-induced obesity reduces dopaminergic neurotransmission in the nucleus accumbens (NAc), and stressful weight loss interventions could promote cravings for palatable foods high in fat and sugar that stimulate dopamine. Activation of κ-opioid receptors (KORs) reduces synaptic dopamine, but contribution of KORs to lower dopamine tone after dietary changes is unknown. Therefore, the purpose of this study was to determine the function of KORs in C57BL/6 mice that consumed a 60% high-fat diet (HFD) for six weeks followed by replacement of HFD with a control 10% fat diet for one day or one week. HFD replacement induced voluntary caloric restriction and weight loss. However, fast-scan cyclic voltammetry revealed no differences in baseline dopamine parameters, whereas sex effects were revealed during KOR stimulation. NAc core dopamine release was reduced by KOR agonism after one day of HFD replacement in females but after one week of HFD replacement in males. Further, elevated plus-maze testing revealed no diet effects during HFD replacement on overt anxiety. These results suggest that KORs reduce NAc dopamine tone and increase food-related anxiety during dietary weight loss interventions that could subsequently promote palatable food cravings and inhibit weight loss.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Hirotaka Shoji ◽  
Tsuyoshi Miyakawa

AbstractThe elevated plus maze test is a widely used test for assessing anxiety-like behavior and screening novel therapeutic agents in rodents. Previous studies have shown that a variety of internal factors and procedural variables can influence elevated plus maze behavior. Although some studies have suggested a link between behavior and plasma corticosterone levels, the relationships between them remain unclear. In this study, we investigated the effects of experience with a battery of behavioral tests, the wall color of the closed arms, and illumination level on the behavior and plasma corticosterone responses in the elevated plus maze in male C57BL/6J mice. Mice were either subjected to a series of behavioral tests, including assessments of general health and neurological function, a light/dark transition test, and an open field test, or left undisturbed until the start of the elevated plus maze test. The mice with and without test battery experience were allowed to freely explore the elevated plus maze. The other two independent groups of naïve mice were tested in mazes with closed arms with different wall colors (clear, transparent blue, white, and black) or different illumination levels (5, 100, and 800 lx). Immediately after the test, blood was collected to measure plasma corticosterone concentrations. Mice with test battery experience showed a lower percentage of open arm time and entries and, somewhat paradoxically, had lower plasma corticosterone levels than the mice with no test battery experience. Mice tested in the maze with closed arms with clear walls exhibited higher open arm exploration than mice tested in the maze with closed arms with black walls, while there were no significant differences in plasma corticosterone levels between the different wall color conditions. Illumination levels had no significant effects on any measure. Our results indicate that experience with other behavioral tests and different physical features of the maze affect elevated plus maze behaviors. Increased open arm time and entries are conventionally interpreted as decreased anxiety-like behavior, while other possible interpretations are considered: open arm exploration may reflect heightened anxiety and panic-like reaction to a novel situation under certain conditions. With the possibility of different interpretations, the present findings highlight the need to carefully consider the test conditions in designing experiments and drawing conclusions from the behavioral outcomes in the elevated plus maze test in C57BL/6J mice.


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