ABSTRACT
Aim To explore the correlation between elevated plus maze (EPM) and elevated zero maze (EZM),as two type animal models of state anxiety in Kunming mice. Methods The behavior of adult,♂/♀,Kunming mice in EPM and EZM was recorded by sequence,for 5 min,with a one-week inter-trial interval. The following parameters were evaluated:percentage of time in open arms (Otime%) and total entries into open and closed arms(Entries). Subsequently,descriptive analysis,fac-tor analysis,cluster analysis,correlation analysis and consisten-cy test were calculated for these parameters. Results T test showed that, compared with EPM, Otime% of EZM (male/fe-male/both sex) decreased, while Entries (male/both sex) in-creased significantly;Fiedman test showed that Otime% (male/female/both sex) and Entries(female/both sex) of both EPM and EZM had great difference between the 5 repeated fragments;Wilcoxon test showed that, compared with EPM, Otime% of EZM in 1st min (male/female/both sex), 2nd min (male/fe-male/both sex),3rd min (female/both sex) decreased, while the Entries in 1st min (male/both sex), 4th min (male/fe-male/both sex),5th min(both sex) increased markedly. Clus-ter analysis showed that EPM and EZM parameters could be clustered into two groups:EPM group and EZM group(male/fe-male/both sex). Factor analysis indicated that the EPM and EZM parameters could be extracted as two factors: EPM factor and EZM factor (male/female/both sex). Correlation analysis displayed either general(in Otime%) or poor(in Entries) cor-relation(male/female/both sex) between EPM and EZM param-eters. Consistency test displayed general consistency (male/fe-male/both sex) in Otime% between EPM and EZM. Conclu-sions Despite of the similar internal principles to induce state anxiety,the different external environment(structure) results in different behavioral patterns,different structure dimensions,fair correlation and concordance between EPM and EZM, and the stable index of EPM and EZM might be preferred to Otime%.
ABSTRACT
Objective To explore the effect of the different doses of oxytocin(OXT) on stress model aggressive behaviour in Wistar rats.Methods According to random number table,40 pregnant rats were divided into experimental stress groups (A, B, C) and control group(D) with 10 samples in each group.Before forced swimming test, rats in experimental groups (A, B, C)were given OXT via intraperitoneal injection with 0.3 mg/kg, 1.0 mg/kg,2.0 mg/kg;rats in group D were given equal volume of normal saline in the same way.At the 3rd day all rats were tested with maternal aggression,including mothers' following indices as total aggression times,biting times,pinning times,attack latency and duration of attack.Elevated plus maze (EPM) test was applied to analyze the behavioral changes.Results In terms of the duration of attack and attack latency,the indexes of group A and group D were significantly different from relevant data ((147.60±23.92) s and(79.70±9.88) s, P＜0.05), while other indexes had no difference(P＞0.05).The duration of attack and attack latency had a significant difference ((3.10±0.87) times, (13.60±5.14)times, (91.30±9.74)s and(167.20±30.02) s, P＜0.01) between group B and group D except total aggression times(P＞0.05).Group C and group D in given indexes had significant differences showing (6.40± 1.34) times, (15.10±4.35) times, (23.70±3.46) times, (49.80± 5.53) s and (215.60± 39.55) s (P＜0.01).Group A and group B in given indexes had significant differences (P＜ 0.05);and group B and group C had a significant difference (P＜0.01)except pinning times(P＞0.05).In EPM ,the open arm entry ratio and the open arm time ratio of both group A and group D were significantly different from respective percentage (0.47±0.13) and (0.13±0.05) (P＜0.01).The significant difference was found in group B and group D(P＜0.01);group A and group B had a statistical difference(P＜0.05);there was no difference in both groups in open arm time ratio(P＞0.05).Conclusion Oxytocin potentially mediates maternal aggression by attenuating stress, and improves the intimate bonding between mother and pups,which means dose dependency of OXT in this process.
ABSTRACT
Glutamate N-methyl-D-aspartate (NMDA) receptor activation within the dorsal column of the periaqueductal gray (dPAG) leads to antinociceptive, autonomic, and behavioral responses characterized as the fear reaction. Activation of NMDA receptors in the brain increases nitric oxide (NO) synthesis, and NO has been proposed to be a mediator of the aversive action of glutamate. This paper reviews a series of studies investigating the effects of neuronal NO synthase (nNOS) inhibition in the dPAG of mice in different aversive conditions. nNOS inhibition by infusion of Nω-propyl-L-arginine (NPLA) prevents fear-like reactions (e.g., jumping, running, freezing) induced by NMDA receptor stimulation within the dPAG and produces anti-aversive effects when injected into the same midbrain site in mice confronted with a predator. Interestingly, nNOS inhibition within the dPAG does not change anxiety-like behavior in mice exposed to the elevated plus maze (EPM), but it reverses the effect of an anxiogenic dose of NMDA injected into the same site in animals subjected to the EPM. Altogether, the results support a role for glutamate NMDA receptors and NO in the dPAG in the regulation of defensive behaviors in mice. However, dPAG nitrergic modulation of anxiety-like behavior appears to depend on the magnitude of the aversive stimulus.
Subject(s)
Animals , Rats , Behavior, Animal , Periaqueductal Gray , Receptors, N-Methyl-D-AspartateABSTRACT
Glycyrrhizae radix (GR) is an herbal medicine that is commonly used in the East Asia for treating a variety of diseases, including stomach disorders. The objective of the present study was to examine the anti-stress effects of GR on repeated stress-induced alterations of anxiety, learning and memory in rats. Restraint stress was administered for 14 days (2 h/day) to the rats in the Control and GR groups (400 mg/kg/day, PO). Starting on the eighth day, the rats were tested for spatial memory on the Morris water maze test (MW) and for anxiety on the elevated plus maze (EPM). We studied the changes of the expressions of cholineacetyl transferase (ChAT) and tyrosine hydroxylase (TH) in the locus coerleus (LC) using immunohistochemistry. The results showed that the rats treated with GR had significantly reduced stress-induced deficits on their learning and memory on the spatial memory tasks. In addition, the ChAT immunoreactivities were increased. Gor the EPM, treatment with GR increased the time spent in the open arms (p<0.001) as compared to that of the control group. Moreover, GR treatment also normalized the increases of the TH expression in the LC (p<0.001). In conclusion, administration of GR improved spatial learning and memory and reduced stress-induced anxiety. Thus, the present results suggest that GR has the potential to attenuate the behavioral and neurochemical impairments caused by stress.