十五肽BPC 157减弱慢性苯丙胺诱导的行为障碍

AIM: To investigate the effect of pentadecapeptide BPC 157 on chronic exposure to amphetamine in rats, particularly the changes commonly referred in chronic amphetamine studies as tolerance ( lesser grade of stereotyped behavior, without increased excitability) and reverse tolerance (ie, prominent stereotyped behavior and heightened startle response upon late amphetamine challenges). METHODS: After initial application (initial single dose-regimen), amphetamine (10 mg/kg, ip) was given once daily till d 5 ( continuous administration-regimen), and thereafter on d 8, 16, and 46 (intermittent administration regimen). For stereotyped behavior and heightened startle response the observation period was 120 min after amphetamine application, and each animal was observed for 10 s in 5 min intervals. Pentadecapeptide BPC 157 (10 μg/kg or 10 ng/kg, ip) or saline (5.0 mL/kg, ip) were given only at the beginning of the experiment, simultaneously with the initial dose of amphetamine. RESULTS: In relation to applied     

Acetazolamide attenuates chemical-stimulated but not thermal-stimulated acute pain in mice

Aim： Acetazolamide （AZA）, a carbonic anhydrase （CA） inhibitor, has been found to alleviate inflammatory and neuropathic pain in rats. In the present study, we investigated the effects of AZA on thermal- and chemical-stimulated acute pain in mice and the possible mechanisms underlying the effects.
Methods： Five acute pain models based on thermal and chemical stimuli were established to investigate the effects of AZA on different types of nociception in mice. The antinociceptive effects of methazolamide （another CA inhibitor） and diazepam （a positive allosteric modulator of GABAA receptor） were also examined. The drugs were administered either intraperitoneally （ip） or intrathecally.

Results： AZA （50–200 mg/kg, ip） did not produce analgesia in two thermal-stimulated acute pain models, ie, mouse tail-flick and hot-plate tests. In contrast, AZA （50–200 mg/kg, ip） dose-dependently reduced paw licking time in both capsaicin and formalin tests in mice. A similar result was observed in a mouse acetic acid-induced writhing test. However, AZA （10 nmol/mouse, intrathecally） did not produce significant analgesia in the 3 chemical-stimulated acute pain models. In addition, methazolamide （50–200 mg/kg, ip） and diazepam （0.25–1.0 mg/kg, ip） did not produce significant analgesia in either thermal- or chemical-stimulated acute pain.

Conclusion： AZA produces analgesia in chemical-stimulated, but not thermal-stimulated acute pain in mice. The attenuation of chemical-stimulated acute pain by AZA may not be due to enhancement of GABAA receptor-mediated inhibition via inhibiting CA activity but rather a peripheral ion channel-related mechanism.     

Tetramethylpyrazine protected photoreceptor cells of rats by modulating nuclear translocation of NF-κB

Aim: To evaluate the effect of tetramethylpyrazine (TMP) injection on retinal damage induced by N-methyl-N-nitrosourea (MNU) in rats and on nuclear factorkappa B (NF-κB) family members. Methods: Female Sprague-Dawley (SD) rats were randomly divided into groups: (i), control group; (ii), model group; and (iii), TMP-injection groups, in which the rats were subdivided into 40 mg/kg, 80 mg/kg and 160 mg/kg groups. Drugs were injected ip into 47-day-old SD rats once a day. At 50 days of age, all rats in the model group and drug groups also received a single ip injection of 60 mg/kg MNU. Rats in group 1 received ip injection of physiological saline. All rats were killed at different times after MNU or physiological saline treatment. The apoptotic index of photoreceptor ceils was calculated by TUNEL labeling; retinal damage was evaluated based on retinal thickness and the expression of NF-nB family members was detected by Western blot. Results: TMP injections, in a dose-dependent manner, suppressed photoreceptor cell apoptosis and decreased its loss in the peripheral retina. As compared with the MNU-treated group, TMP injection at a dose of 160 mg/kg also timedependently upregulated the NF-κB/p65 protein level in the nucleus and downregulated the IκBα protein level in the cytoplasm. However, no protective effect of TMP injection on MNU-induced central retinal damage was found. Conclusion: TMP injection partially protects against MNU-induced retinal damage by upregulating the nuclear translocation of p65 to inhibit photoreceptor cells apoptosis.     

阿片样物质介导多潘立酮和西沙必利对小鼠的镇痛作用

To study the anti-nociceptive effect of domper-idone and cisapride in mice. METHODS: Initially, the effect of these drugs on motor activity was tested using rotarod. The anti-nociception was tested using chemical and mechanical assay. In the chemical assay, the number of abdominal constrictions either in the saline treated animals or in the domperidone/cisapride (1, 5, or 10 mg/kg either po or ip) treated mice, were recorded for a period of 30 min after acetic acid challenge (10 mLAg, of 0.6 % acetic acid ip). In the tail clip assay, the time taken by the mouse to make attempts to dislodge the bulldog clamp placed at the tail (reaction time) was recorded with a cut off time of 30 s. The role of opioid pathways was examined by pretreating the animals with naloxone (1 mg/kg, ip) 30 min prior to domperidone and cisapride. RESULTS: Domperidone and cisapride, both reduced the number of abdominal constrictions when given orally or intraperitoneally. Domperidone (5 mg/kg) inhibited it to the extent of 57.0 % a     

磷化铝中毒抑制大鼠胆碱酯酶及阿托品和氯解磷啶的作用(英文)

AIM: To investigate the cholinesterase inhibition and ef-fect of atropine and pralidoxime (PAM) treatment on theSurvival time in the rat model of aluminium phosphide(AlP) poisoning. METHODS: The rats were treatedwith AlP (10 mg/kg; 5.55×LD_(50); ig) and the survivaltime was noted. The effect of atropine (1 mg/kg, ip)and PAM (5 mg/kg, ip) was noted on the above. At-ropine and PAM were administered 5 min after AlP.Plasma cholinesterase levels were measured spectropho-     

A role for the prefrontal cortex in stress- and cocaine-induced reinstatement of cocaine seeking in rats

Rationale and objective. It is well established that stress induces reinstatement of drug seeking in an animal model of relapse. Here we studied the role of the medial prefrontal cortex (mPFC) and orbitofrontal cortex (OFC) in foot-shock stress-induced reinstatement of cocaine seeking. Methods. Groups of rats were trained to self-administer cocaine (0.5 mg/kg per infusion, i.v., 3 h/day for 9 days) and after ten drug-free days were exposed to extinction and reinstatement test sessions. Each 60 min of extinction was separated by a 30-min time-out period after which the lever and stimulus lights were reintroduced. Rats were given four 1-h extinction sessions on day 1 and then on subsequent days were given two to three 1-h extinction sessions that were followed by a 3-h test for reinstatement. Tests were run every 48 h. In one set of experiments, the effects of inactivation of the prelimbic (PL), infralimbic (IL) or OFC by tetrodotoxin (TTX, 5 ng/0.5 μl per side) on reinstatement induced by foot shock (5 min, intermittent, 1 mA) or priming injections of cocaine (20 mg/kg, i.p.) were determined. In a second set, the effects of infusions of the D1-like and D2-like dopamine receptor antagonists (SCH 23390 and raclopride) were studied using the same methods. Results. TTX infusions into the PL cortex blocked both foot shock and cocaine-induced reinstatement. TTX into OFC attenuated foot-shock-induced, but not cocaine-induced reinstatement. Infusions into IL were ineffective. Infusions of SCH 22390 (0.25 μg/0.5 μl per side) into either PL or OFC blocked foot-shock-induced reinstatement, but infusions into PL had no effect on cocaine-induced reinstatement. Raclopride (5 μg/0.5 μl per side) had no effect on foot-shock-induced reinstatement in either PL or OFC or on cocaine-induced reinstatement when infused into PL. Neither TTX nor SCH23390 infusions into PL or OFC had any effect on lever pressing for sucrose. Conclusions. These results suggest that the PL and OFC regions form part of the circuitry mediating the effects of foot shock stress on reinstatement of drug seeking and that the PL region may be a common pathway for cue, drug and foot-shock stress-induced reinstatement of drug seeking.     

Predisposition to self-administer amphetamine: the contribution of response to novelty and prior exposure to the drug

 The present experiment examined the contribution of locomotor response to novelty and prior exposure to amphetamine to rats’ predisposition to self-administer a low dose of the drug. Rats were screened for their locomotor response to a novel environment and divided into high (HR) or low (LR) responders based on whether their locomotor scores were above or below the median activity level of the subject sample. Animals were then pre-exposed to nine daily injections of either saline (1 ml/kg, IP) or amphetamine (1.5 mg/kg, IP). Starting 1 week after pre-exposure, animals in the four different groups (HR pre-exposed to saline or amphetamine; LR pre-exposed to saline or amphetamine) were given the opportunity, in each of ten daily sessions, to lever press for a low dose of amphetamine (10 μg/kg per infusion) in a two lever (active versus inactive) continuous reinforcement operant task. Initial lever press performance revealed no difference in active versus inactive lever pressing between amphetamine and saline pre-exposed animals. However, in agreement with previous reports, with successive test sessions amphetamine pre-exposed rats maintained higher levels of active versus inactive lever pressing for drug while saline pre-exposed rats showed a progressive decrease in the pressing of either lever. Interestingly, this enhanced active lever pressing was observed in HR but not LR rats pre-exposed to amphetamine. In addition, HR saline pre-exposed animals showed initial active versus inactive lever pressing equivalent to that of HR amphetamine pretreated rats but this enhanced responding for drug diminished over days and by the last day of self-administration was indistinguishable from that of LR animals having been pre-exposed either to amphetamine or saline. These findings confirm that prior exposure to amphetamine promotes the subsequent self-administration of the drug and suggest that response to novelty may be a predictor more closely linked to an animal’s propensity to become sensitized to the facilitatory effects of the drug rather than to an animal’s current sensitization state and predisposition to self-administer the drug. Received: 6 July 1996 / Final version: 5 October 1996     

5-Hydroxytryptamine-inhibiting property of Feverfew: role of parthenolide content

AIM: To study the mechanism of antimigraine activity of Tanacetum parthenium ( Feverfew), its extracts and parthenolide, a component of Feverfew, by observing their effect on 5-HT storage and release, and stimulation of 5-HT2B and 5-HT2A receptors. Also to standardize a dosage form of Feverfew with respect to its parthenolide content. METHODS: Isometric responses to 5-HT and an indirect acting serotonergic, d-fenfluramine, were obtained on rat fundus and ileum. In one set of experiments the effect of dichloromethane extract of Feverfew and parthenolide was observed on the above. The extract was then thermally degraded upto 10 %, 23 %, and 33 % with respect to its parthenolide content by keeping at 60℃ and 75 % relative humidity and the experiments were repeated. In another set of experiments rats were fed with 20 mg/kg Feverfew powder (equivalent to a human dose of 500 μg parthenolide per day) for 30 d or were ip injected with parthenolide (23.4 μg/day) for 7 d. In the same set of experiments one gro     

Protective role of methylene blue in kidney and jejunum injuries of rats by paraquat北大核心CSCD

OBJECTIVE: To investigate the antidotal ability and mechanisms of methylene blue (MB) against paraquat (PQ)-poisoned kidney and jejunum injuries in rats. METHODS: Male Sprague-Dawley rats were randomly divided into 6 groups(n=6): normal control group(0.2 mL 0.9% saline solution, ip), MB group (MB 2 mg·kg-1, ip), PQ group (PQ 35 mg·kg-1, ip), PQ+MB ig therapy group (PQ 35 mg·kg-1, ip; MB 2 mg·kg-1, ig), PQ+MB ip therapy group (PQ 35 mg·kg-1, ip, and MB 2 mg·kg-1, ip), and PQ+MB 2 h ip therapy group (PQ 35 mg·kg-1, ip; 2 h later MB 2 mg·kg-1, ip). 48 h later, the content of blood urea nitrogen (BUN) and creatinine(Cr), the activity of superoxide dismutase (SOD) and myeloperoxidase (MPO), the content of adenosine triphosphate (ATP) and malonaldehyde (MDA) in the kidney and jejunum tissues were determined. The pathological changes were detected by HE staining, apoptosis by terminal deoxyuridine triphosphate deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) assay, and the expression of heme oxygenase-1 (HO-1) protein in the kidney by immunohistochemistry. RESULTS: Compared with normal control and MB group, the injury scores of kidney and jejunum in PQ group were increased (P<0.05), the content of BUN and Cr was increased (P<0.05), the activity of SOD and the content of ATP were decreased (P<0.05, P<0.01), the activity of MPO and the content of MDA were increased (P<0.05, P<0.01), and the apoptosis rate of the kidney and jejunum was increased(P< 0.01). Compared with PQ group, the injury scores of the kidney and jejunum in all three MB treatment groups were decreased (P<0.05), the content of BUN and Cr was decreased (P<0.05), the activity of SOD and the content of ATP were increased (P<0.05, P<0.01), the activity of MPO and the content of MDA were decreased (P<0.05), the apoptosis rate of the kidney and jejunum was decreased (P<0.01), and the immunhistochemical score of HO-1 in kidney tissue was increased (P<0.05). CONCLUSION: MB can alleviate PQ-poisoned kidney and jejunum injuries, which may be related to up-regulated expressions of HO-1.     

Uterotrophic assay,Hershberger assay,and subacute oral toxicity study of 4,4´-[1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bis[phenol] based on the OECD draft protocols

We performed an uterotrophic assay, the Hershberger assay, and a 28-day repeated-dose toxicity study (enhanced OECD test guideline No. 407) of 4,4′-[1-[4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl]ethylidene]bis[phenol] based on the OECD draft protocols. In the uterotrophic assay, female SD rats were subcutaneously injected with the chemical at doses of 0, 100, 300, and 1,000 mg/kg on each of 3 days from postnatal day 20 to day 22, and the uterine weight of rats given the 1,000 mg/kg dose of the test chemical plus ethinyl estradiol decreased. In the Hershberger assay, the test chemical was orally administered at doses of 0, 100, 300, and 1,000 mg/kg day to castrated male SD rats for ten consecutive days beginning on postnatal day 56, and no changes were observed. On the other hand, when the test chemical was orally administered at doses 0, 100, 300, and 1,000 mg/kg day for at least 28 days, a decrease in LH values in rats of both sexes and a decrease in FSH and estradiol values in female rats were detected in the 1,000 mg/kg group, and abnormal estrous cycles, uterine glandular atrophy, persistence of ovarian corpora lutea, vaginal epithelial mucification, and mammary glandular hyperplasia were also observed in one female rat in the 1,000 mg/kg group. Therefore, the uterotrophic assay used in this study showed that the chemical has the estrogen–antagonist properties, and some potentially endocrine-mediated effects were detected in growing rats based on the results of the enhanced OECD test guideline No. 407. However, the changes were observed in rats given a high dose of the chemical, 1,000 mg/kg day.     

Comparative effects of valproate,anxiolytic, or anxiogenic drugs on the light/dark aversion test

The potential anxiolytic-like effects of 200, 300, and 400 mg/kg i.p. of sodium valproate were evaluated in the light/dark aversion test in mice. For comparison, we included the reference anxiolytic drug, diazepam (2.5, 5.0, 10 mg/kg i.p.) as well as putative anxiolytics, i.e., clonidine (0.015, 0.030, 0.060 mg/kg i.p.), verapamil (5, 10, 20 mg/kg i.p.), or anxiogenic drugs, pentylenetetrazol (5, 10, 15 mg/kg i.p.). Results showed that control mice preferred the dark compartment where they spent approximately 70% of their time. After administration of 5 and 10 mg/kg i.p. of diazepam or 400 mg/kg i.p. of valproate, the increase in exploratory behavior in the lit area was associated with an increase both in the number of transitions and in the time spent in the lit area. Pretreatment with 0.030 and 0.060 mg/kg i.p. clonidine caused an increase in the time spent in the lit area. Verapamil had no significant effect on both measures of this test. Pentylenetetrazol, in doses which did not cause convulsions, was anxiogenic. In conclusion, these results in the light/dark aversion test are consistent with clinical data showing that valproate, a GABA-agonist, and clonidine, an α₂ adrenoceptor agonist, possess anxiolytic properties. © 1992 Wiley-Liss, Inc.     

Intrastrain variations in anxiolytic effect of nitrazepam in mice

This study investigated the individual differences in the baseline anxiety and anxiolytic effect of nitrazepam in Balb/c mice. Initially mice were sorted according into low, intermediate and high anxiety groups (LA, IA and HA) based on the number of entries to and time spent in open arms in elevated plus maze. Later, anxiolytic effect of nitrazepam (2 mg/kg, p.o) in LA, IA and HA mice was evaluated using hole board and light/dark tests. In Hole board test, LA mice made more number of head dippings and spent more time during head dippings, while HA mice made less number of head dippings and spent less time during head dipping when compared to that of IA mice. In light/dark test LA mice made more reentries to and spent more time in bright compartment, while HA mice made few reentries to and spent less time in bright compartment. Results suggest that mice of a single strain differ in their baseline anxiety and anxiolytic effect of nitrazepam.     

A fully automated light/dark apparatus useful for comparing anxiolytic agents

The effects of known anxiolytic agents and putative anxiolytic agents were assessed in mice in a fully automated 2-compartment light/dark test. Significant increases in lit area activities (e.g., time spent in the lit area, locomotor activity, rearing behavior) were used as possible indicators of anxiolytic-like action. The measurement found most consistent and useful for assessing antianxiety-like activity was the time mice spent in the lit area. The benzodiazepine, diazepam; the 5-HT1A agent, ipsapirone; and the 5-HT3 receptor antagonist, ondansetron, produced significant anxiolytic-like activity between doses of 1.0 to 10.0 mg/kg, 17.8 to 31.6 mg/kg, and 0.0001 to 1.0 mg/kg respectively. The 5-HT1A receptor agonist, 8-OH DPAT, also exhibited anxiolytic-like action between doses of 0.0005 to 3.16 mg/kg. In contrast, the peripheral 5-HT3 receptor agonist, N-phenylbiguanide; the antidepressant, imiprame; the neuroleptic, chlorpromazine; and the CNS stimulat, S(+)-amphetamine, did not display antianxiety-like activity. The positive results obtained for the three types of compounds (benzodiazepine, 5-HT1A, and 5-HT3) indicate that this fully automated light/dark apparatus may be useful for identifying known and putative anxiolytic agents.     

Isolation and anxiolytic activity of 3,4-bis(3,4-dimethoxyphenyl)furan-2,5-dione from the ethanolic extract of heart wood of Cedrus deodara

Cedrus deodara heart wood has been traditionally used for the treatment of anxiety. The objective of the study was to isolate the compound from the ethanolic extract and to investigate the anxiolytic activity. The isolated compound was characterized by FTIR, ¹H NMR, ¹³C NMR, and mass spectral technique. The spectral data revealed the structure?3,4-bis(3,4-dimethoxyphenyl) furan-2,5-dione (BDFD). Anxiolytic activity of BDFD was evaluated using elevated plus maze (EPM), Open- field test (OFT) and light–dark model (LDM) in mice. Control mice were orally treated with an equal volume of vehicle (4% gum acacia), and positive control mice were treated with diazepam. In EPM, diazepam and BDFD treated (100?mg/kg) mice exhibited a significant increase in the number of open arm entries and time spent in the open arms (P?<?0.001). In OFT, like diazepam BDFD treated mice (100?mg/kg) increased the ambulation (P?<?0.001). In LDM, BDFD treated mice (30 and 100?mg/kg) also showed a significant (P?<?0.001) increase in the time spent in light arena. In conclusion, the anxiolytic activity of BDFD upon the anxiety models showed a promising result and could be useful for primary medical care.     

Sex differences in the burying behavior test in middle-aged rats: effects of diazepam

The full behavioral profile displayed during the burying behavior test was studied in middle aged (11-14 months) males, females with irregular estrous cycles, and females in persistent diestrus, with and without diazepam (0.5-2.0 mg/kg). Ambulation and motor coordination were also tested to discern behavioral changes from general motor alterations. Without diazepam treatment, middle-aged males showed longer burying behavior latencies, more prod explorations and less freezing than both groups of females. Untreated middle aged males also showed less cumulative burying and more immobility compared to females with irregular cycles. None of the parameters showed any difference between the female groups. Diazepam (0.5 and 1.0 mg/kg) increased burying behavior latency in females, but had no effect on any parameter in middle aged males. However, a higher dose (2.0 mg/kg) of diazepam increased immobility, freezing and the number of prod shocks and decreased prod explorations and groomings, but impaired motor coordination in males. In contrast with young males and females, diazepam at any dose reduced cumulative burying. Data are discussed on the bases of (1) sex and age differences in burying behavior and on (2) the anxiolytic-like action of diazepam and its side effects.     

Pharmacologically distinctive behaviors other than burying marbles during the marble burying test in mice

In the marble burying test, we focused on the 5 distinctive behavioral parameters of mice other than burying marbles, i.e. digging, latency to the first digging, exploration around marbles, rearing and locomotor activity. Typical anxiolytics or antidepressants with different mechanisms, fluvoxamine (30 mg/kg, selective serotonin reuptake inhibitor), bupropion (60 mg/kg, noradrenaline and dopamine reuptake inhibitor), imipramine (60 mg/kg, tricyclic antidepressant) and diazepam (10 mg/kg, benzodiazepine) were used to examine whether these behavioral parameters are sensitive to pharmacological treatments. Each of the drugs demonstrated an individual action pattern on the 4 behavioral parameters (latency to the first digging, exploration around marbles, rearing and locomotor activity). On the other hand, all 4 drugs reduced burying marbles and digging, which were correlated with each other. These results suggest that the former 4 behavioral parameters are sensitive to pharmacological treatment and that pharmacological regulation mechanisms of them may be different from burying marbles and digging. They could be useful to identify the type of action of a test drug like selective serotonin reuptake inhibitor, noradrenaline and dopamine reuptake inhibitor, tricyclic antidepressant or benzodiazepine.     

Anxiolytic-like effects of inhaled linalool oxide in experimental mouse anxiety models

Linalool oxide is a monoterpene that is found in some species of aromatic plants. The effects of the inhalation of linalool oxide (0.65%, 1.25%, 2.5% and 5.0% w/w) in the elevated plus-maze and light/dark box tests as animal models of anxiety were investigated in adult male mice and compared with the effects of the reference anxiolytic diazepam (0.5 and 2.0 mg/kg), administered intraperitoneally. Additionally, the effects of inhaled linalool oxide were investigated in the rotarod test. Linalool oxide significantly increased the number of visits to the open arms of the elevated plus-maze and the amount of time spent there as well as the total number of entries. In the light/dark box test, inhalation of linalool oxide led to an increase in the time spent by the mice in the brightly-lit chamber and in the number of times the animal crossed from one compartment to another. Performance on the rotarod was unaffected. Thus, inhaled linalool oxide was found to have anxiolytic properties in both animal models, without causing any motor deficit. These results suggest that inhalation of linalool oxide may be a useful means of counteracting anxiety.     

Effect of Morus alba L. (mulberry) leaves on anxiety in mice

Objective:

The aim of the present work is to evaluate the anxiolytic effect of a methanolic extract of Morus alba L. leaves in mice.

Materials and Methods:

The hole-board test, elevated plus-maze paradigm, open field test, and light/dark paradigm were used to assess the anxiolytic activity of the methanolic extract of M. alba L. Morus alba extract (50, 100, and 200 mg/kg, i.p.) and diazepam (1 mg/kg, i.p.) were administered 30 min before the tests.

Results:

The results showed that the methanolic extract of M. alba significantly increased the number and duration of head poking in the hole-board test. In the elevated plus-maze, the extract significantly increased the exploration of the open arm in similar way to that of diazepam. At a dose of 200 mg/kg i.p. the extract significantly increased both the time spent in and the entries into the open arm by mice. Further, in the open field test, the extract significantly increased rearing, assisted rearing, and number of squares traversed, all of which are demonstrations of exploratory behavior. In the light/dark paradigm, the extract produced significant increase in time spent in the lighted box as compared to vehicle. The spontaneous locomotor activity count, measured using an actophotometer, was significantly decreased in animals pretreated with M. alba extract, indicating a remarkable sedative effect of the plant.

Conclusion:

The results of the present study suggest that a methanolic extract of M. alba leaves may possess an anxiolytic effect.     

Influence of prior maze experience on behaviour and response to diazepam in the elevated plus-maze and light/dark tests of anxiety in mice

A single prior undrugged exposure to the elevated plus-maze has been reported to reduce open arm activity on retest and to attenuate/abolish the anxiolytic response to benzodiazepines at retest intervals ranging from 48 h to 14 days. The present study was designed to examine the generality of these findings by comparing the effects of prior maze experience on baseline behaviour and response to diazepam in two murine models of anxiety. Parallel experiments were conducted in which DBA/2 mice were exposed/not exposed to the plus-maze, treated daily with saline or diazepam (2–4 mg/kg daily for 8 days) and then tested on either the elevated plus-maze or in the light/dark test of exploration. Results show that, in both tests, diazepam reduced behavioural indices of anxiety in maze-naive mice only. However, interpretation of this apparent loss of diazepam efficacy is at least partially confounded by the observation that maze experience per se altered baseline behaviour in both procedures,reducing open arm activity in the plus-maze andincreasing light compartment activity in the light/dark test. The apparent elimination of an anxiolytic response to diazepam in two animal models of anxiety by prior plus-maze experience is discussed in relation to experience-related baseline shifts in behaviour.     

The effects of angelica essential oil in three murine tests of anxiety

The effects of angelica essential oil in three assays predictive of anxiolytic activity in male mice were studied, with diazepam as a positive anxiolytic control. In the elevated plus-maze test, compared to the positive control diazepam, angelica essential oil (30.0 mg/kg, PO) had a modest anxiolytic-like effect (increased the percentage of open-arm time and reduced the percent protected head dips). In the light/dark test, angelica essential oil (30.0 mg/kg) prolonged the time spent in the light area without altering the locomotor activity of the animals. In the stress-induced hyperthermia test, 60 and 70 min after drug administration, rectal temperature was measured twice, angelica essential oil at the dose of 30.0 mg/kg inhibited stress-induced hyperthermia. Thus, these findings indicate that angelica essential oil, as does diazepam, exhibits an anxiolytic-like effect. Further studies will be required to assess the generality of the present findings to other species and behavioural paradigms.