Creatine@SiO2 @Fe3 O4 nanocomposite as an efficient sorbent for magnetic solid-phase extraction of escitalopram and chlordiazepoxide from urine samples through quantitation via HPLC-UV.

An efficient, cost-effective, and fast-synthesis method is presented in the current study to prepare magnetic nanoparticles covered by cheap and nitrogen-rich creatine. The hydrothermal method was used for the synthesis of the magnetic core. The prepared magnetic core was then covered by SiO2 and subsequently functionalized using creatine. The prepared creatine@SiO2 @Fe3 O4 was utilized as a sorbent in the magnetic solid-phase extraction of the selected antidepressants including escitalopram and chlordiazepoxide as the model drugs. The extracted drugs were desorbed by a suitable organic solvent and analyzed by high-performance liquid chromatography equipped with an ultraviolet detection system. The influence of different variables on the magnetic solid-phase extraction method was examined by the Plackett-Burman and Box-Behnken designs for screening and optimization, respectively. Under the obtained optimum conditions, the linear ranges of the method were found to be in the range of 1-500 µg L-1 . The limits of detection and limits of quantification were in the range of 0.27-0.63 µg L-1 and 0.89-1.93 µg L-1 for the selected analytes, respectively. Furthermore, the enrichment factors were found to be 79.8 and 92.7 for chlordiazepoxide and escitalopram, respectively. The method was successfully employed for the analysis of selected drugs in urine samples.

New Saccharin Salt of Chlordiazepoxide: Structural and Physicochemical Examination.

Since the formation of organic salts can improve the solubility, bioavailability, and stability of active pharmaceutical ingredients, the aim of this work was to prepare an organic salt of chlordiazepoxide with saccharin. To achieve this goal, the saccharin salt of chlordiazepoxide was obtained from a physical mixture of both components by grinding them with a small volume of solvent and by crystallizing them with complete evaporation of the solvent. The resulting salt was examined by methods such as Powder X-ray Diffraction (PXRD), Single Crystal X-ray Diffraction (SCXRD), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Fourier Transform Infrared (FT-IR), and Raman spectroscopy. The results of the studies proved that saccharin salt of chlordiazepoxide crystallizes in the orthorhombic Pbca space group with one chlordiazepoxide cation and one saccharin anion in the asymmetric unit. In the crystal of the title compound, the chlordiazepoxide cation and the saccharin anion interact through strong N-H···O hydrogen bonds and weak C-H···O hydrogen bonds. The disappearance of the N-H band in the FT-IR spectrum of saccharin may indicate a shift of this proton towards chlordiazepoxide, while the disappearance of the aromatic bond band in the chlordiazepoxide ring in the Raman spectrum may suggest the formation of intermolecular hydrogen bonds between chlordiazepoxide molecules. The melting point of the salts differs from that of the starting compounds. Thermal decomposition of the salt begins above 200 °C and shows at least two overlapping stages of mass loss. In summary, the results of the research showed that the crystalline salt of the saccharin and chlordiazepoxide can be obtained by various methods: grinding with the addition of acetonitrile and crystallization from acetonitrile or a mixture of methanol with methylene chloride.

Synthesis of mesoporous silica for adsorption of chlordiazepoxide and its determination by HPLC: Experimental design.

In this work, mesoporous silica (SBA-15-NH2 ) was used as an efficient adsorbent for extraction of chlordiazepoxide from different samples based on dispersive nanomaterial-ultrasound assisted microextraction followed by high-performance liquid chromatography. The prepared sorbent was characterized by fourier transform infrared spectroscopy, scanning electron microscopy, low-angle X-ray diffraction, thermal analysis, and N2 adsorption-desorption surface area measurement. Several variables affecting the extraction efficiency of the chlordiazepoxide, including the amounts of adsorbent, time of adsorption, pH and volume of desorption solvent were optimized by central composite design combined with desirability function. The values of variables were set as 10 mg of SBA-15-NH2 , 15 min adsorption time, pH = 7.3 and 1 mL methanol. The linear response (0.998) was obtained in the range of 0.006-10 µgmL-1 with detection limit 0.0014 µg/mL and extraction recovery was in the range of 91-96% with relative standard deviation < 6%.

Stevens-Johnson Syndrome Associated With Chlordiazepoxide.

Objective: To report a case of chlordiazepoxide-associated Stevens-Johnson syndrome (SJS). Case Summary: This case provides insight into a serious adverse drug reaction secondary to a drug not commonly associated with SJS. A 29-year-old female presented with a 4-day history of rash and pruritus. The rash started on her arms and spread all over her body. The patient was started on chlordiazepoxide 3½ weeks ago. On examination, there were multiple, raised, round erythematous lesions in various stages of healing. Skin erosions were noted on her lips and buccal mucosa. However, the rash did not involve the conjunctiva, inner ears, or genitalia. The patient was discharged home with a follow-up appointment with dermatology and instructions to discontinue chlordiazepoxide. Two days after her initial presentation, the patient's rash spread to her eyes and genitalia. A painful, white film developed on her tongue, and she was unable to tolerate oral intake. She was emergently sent back to hospital and transferred to a Burn Unit. The biopsy report revealed full-thickness necrotizing keratinocytes in the epidermis consistent with SJS. Discussion: To our knowledge, there is only one other case report of chlordiazepoxide-associated SJS. Chlordiazepoxide is thought to be the cause of this patient's biopsy-confirmed SJS and overall presentation. SJS is a rare but serious condition that is usually a result of drug exposure. Conclusions: The close temporal relationship between chlordiazepoxide initiation and onset of SJS provides a convincing theory as to the etiology of SJS in our patient.

Anxiogenic role of vasopressin during the early postnatal period: maternal separation-induced ultrasound vocalization in vasopressin-deficient Brattleboro rats.

Both animal and human studies suggest that in adulthood, plasma vasopressin level correlates well with anxiety. Little is known about the mood regulation during the perinatal period. Here, we aim to investigate the influence of vasopressin on anxiety during the early postnatal age. As a sign of distress, rat pups emit ultrasonic vocalizations (USVs) when they are separated from their mother. This USV was detected in 7- to 8-day-old vasopressin-deficient Brattleboro pups, and they were compared to their heterozygote littermates and wild-type pups. The results were confirmed by V1b antagonist treatment (SSR149415 10 mg/kg ip 30 min before test) in wild-types. Chlordiazepoxide (3 mg/kg ip 30 min before test)-an anxiolytic-was used to test the interaction with the GABAergic system. At the end of the test, stress-hormone levels were measured by radioimmunoassay. Vasopressin-deficient pups vocalized substantially less than non-deficient counterparts. Treatment with V1b antagonist resulted in similar effect. Chlordiazepoxide reduced the frequency and duration of the vocalization only in wild-types. Reduced vocalization was accompanied by smaller adrenocorticotropin levels but the level of corticosterone was variable. Our results indicate that the anxiolytic effect of vasopressin deficiency (both genetic and pharmacological) exists already during the early postnatal age. Vasopressin interacts with the GABAergic system. As mood regulation does not go parallel with glucocorticoid levels, we suggest that vasopressin might have a direct effect on special brain areas.

Validated green high-performance liquid chromatographic methods for the determination of coformulated pharmaceuticals: a comparison with reported conventional methods.

The introduction of sustainable development concepts to analytical laboratories has recently gained interest, however, most conventional high-performance liquid chromatography methods do not consider either the effect of the used chemicals or the amount of produced waste on the environment. The aim of this work was to prove that conventional methods can be replaced by greener ones with the same analytical parameters. The suggested methods were designed so that they neither use nor produce harmful chemicals and produce minimum waste to be used in routine analysis without harming the environment. This was achieved by using green mobile phases and short run times. Four mixtures were chosen as models for this study; clidinium bromide/chlordiazepoxide hydrochloride, phenobarbitone/pipenzolate bromide, mebeverine hydrochloride/sulpiride, and chlorphenoxamine hydrochloride/caffeine/8-chlorotheophylline either in their bulk powder or in their dosage forms. The methods were validated with respect to linearity, precision, accuracy, system suitability, and robustness. The developed methods were compared to the reported conventional high-performance liquid chromatography methods regarding their greenness profile. The suggested methods were found to be greener and more time- and solvent-saving than the reported ones; hence they can be used for routine analysis of the studied mixtures without harming the environment.

The effects of lactation on impulsive behavior in vasopressin-deficient Brattleboro rats.

Vasopressin (AVP)-deficient Brattleboro rats develop a specific behavioral profile, which-among other things-include altered cognitive performance. This profile is markedly affected by alterations in neuroendocrine state of the animal such as during lactation. Given the links between AVP and cognition we hypothesized that AVP deficiency may lead to changes in impulsivity that is under cognitive control and the changes might be altered by lactation. Comparing virgin and lactating AVP-deficient female Brattleboro rats to their respective controls, we assessed the putative lactation-dependent effects of AVP deficiency on impulsivity in the delay discounting paradigm. Furthermore, to investigate the basis of such effects, we assessed possible interactions of AVP deficiency with GABAergic and serotonergic signaling and stress axis activity, systems playing important roles in impulse control. Our results showed that impulsivity was unaltered by AVP deficiency in virgin rats. In contrast a lactation-induced increase in impulsivity was abolished by AVP deficiency in lactating females. We also found that chlordiazepoxide-induced facilitation of GABAergic and imipramine-induced enhancement of serotonergic activity in virgins led to increased and decreased impulsivity, respectively. In contrast, during lactation these effects were visible only in AVP-deficient rats. These rats also exhibited increased stress axis activity compared to virgin animals, an effect that was abolished by AVP deficiency. Taken together, AVP appears to play a role in the regulation of impulsivity exclusively during lactation: it has an impulsivity increasing effect which is potentially mediated via stress axis-dependent mechanisms and fine-tuning of GABAergic and serotonergic function.

Simultaneous determination of chlordiazepoxide and selected antidepressants using CZE.

A simple CE method was developed and validated for the simultaneous determination of chlordiazepoxide (CHL), amitriptyline, and nortriptyline (mixture I) or the determination of CHL and imipramine (mixture II) using the same BGE. Sertraline and amitriptyline were used as internal standards for the first and second mixtures, respectively. The method allows amitriptyline to be completely separated from its impurity and main metabolite nortriptyline, which can be quantified from 0.2 µg/mL. The separation was achieved using 20 mM potassium phosphate buffer pH 5 containing 12 mM ß-cyclodextrin and 1 mM carboxymethyl-ß-cyclodextrin. UV detection was performed at 200 nm and a voltage of 15 kV was applied on an uncoated fused-silica capillary at 25°C. These experimental conditions allowed separation of the compounds to be obtained in 7 min. Calibration graphs proved the linearity up to 40 µg/mL for CHL, up to 100 µg/mL for amitriptyline and imipramine, and up to 5 µg/mL for nortriptyline. The accuracy and precision of the method have been determined by analyzing synthetic mixtures and pharmaceutical formulations. The analytical results were quite good in all cases indicating that the method was linear, sensitive, precise, accurate, and selective for both mixtures.

Further disentangling the motivational processes underlying benzodiazepine hyperphagia.

In addition to their well-known anxiolytic functions, benzodiazepines produce hyperphagia. Previously, we reported that the benzodiazepine, chlordiazepoxide (CDP), increased consumption of both normally-preferred and normally-avoided taste stimuli during long-term (1 h) tests, primarily through changes in licking microstructure patterns associated with hedonic taste evaluation, whereas there was little effect on licking microstructure measures associated with post-ingestive feedback. In this study, we further examined the hedonic and motivational specificity of CDP effects on ingestive behavior. We tested brief access (15 s) licking responses for tastants spanning all taste qualities after treatment with either CDP (5 or 10 mg/kg) or the non-benzodiazepine anxiolytic, buspirone (1.5 or 3 mg/kg). A between-subjects, counterbalanced design compared the CDP or buspirone effects on licking responses for water and a range of weak to strong concentrations of NaCl, Q-HCl, citric acid, MSG, saccharin, and capsaicin under water-restricted (23 h) conditions; and sucrose, saccharin, and MSG under water-replete conditions. In a dose dependent manner, CDP increased licking for taste stimuli that were normally-avoided after saline treatment, with a notable exception observed for the trigeminal stimulus, capsaicin, which was not affected at any concentration or drug dose, suggesting a taste-specific effect of CDP on orosensory processing. Under water-replete conditions, CDP dose-dependently increased licking to normally-accepted concentrations of sucrose, saccharin, and MSG. There was no effect of either drug on licks for water under either water-restricted or water-replete conditions. Buspirone slowed oromotor coordination by increasing brief interlick intervals, but it did not affect licking for any concentrations of the tastants. Overall, these results indicate that benzodiazepines selectively enhance the hedonic acceptance of gustatory orosensory stimuli, independent of general anxiolytic or oromotor coordination effects, or physiological states such as thirst.

Chlordiazepoxide-induced delirium in a patient undergoing alcohol withdrawal: a case report.

BACKGROUND: Ethanol dependence is associated with a discontinuation withdrawal delirium. Chlordiazepoxide is frequently successfully used in its treatment. CASE PRESENTATION: A 27-year-old, Caucasian female with ethanol dependence who had objective symptoms of withdrawal experienced worsening of her delirium after administration of chlordiazepoxide, but improved with lorazepam and cleared with discontinuation of benzodiazepine administration. CONCLUSIONS: Worsening of delirium appears to be related to the specific use of chlordiazepoxide, but the mechanism of this effect is not clear. While this case does not alter the standard care of ethanol dependence, it does alert clinicians that our treatment approach may not be fully benign.

Effects of chlordiazepoxide on pausing during rich-to-lean transitions.

Extended pausing during discriminable transitions from rich-to-lean conditions can be viewed as escape (i.e., rich-to-lean transitions function aversively). Thus, an anxiolytic drug would be predicted to mitigate the aversiveness and decrease pausing. In the current experiment, pigeons' key pecking was maintained by a multiple fixed-ratio fixed-ratio schedule of rich (i.e., larger) or lean (i.e., smaller) reinforcers. Intermediate doses (3.0-10.0 mg/kg) of chlordiazepoxide differentially decreased median pauses during rich-to-lean transitions. Relatively small decreases in pauses occurred during lean-to-lean and rich-to-rich transitions. Effects of chlordiazepoxide on pausing occurred without appreciable effects on run rates. These findings suggest that signaled rich-to-lean transitions function aversively.

Continuous Intravenous Flumazenil Infusion Used in Iatrogenic Chlordiazepoxide Overdose in the Setting of Alcoholic Withdrawal Syndrome Management.

Chlordiazepoxide is a benzodiazepine that is widely used in the treatment of alcohol withdrawal syndrome (AWS). Flumazenil is a competitive antagonist at the benzodiazepine receptor site and is the drug of choice for the treatment of benzodiazepine overdose. Reversal of benzodiazepine overdose is usually achieved by the use of a flumazenil bolus; however, the continuous infusion has been used when concomitant medical conditions may lead to delayed metabolism of the benzodiazepine involved. We present a patient with AWS, with inadvertent chlordiazepoxide overdose treated effectively with a prolonged flumazenil infusion.

Efficacy and Safety of Clidinium/Chlordiazepoxide as an Add-on Therapy in Functional Dyspepsia: A Randomized, Controlled, Trial.

BACKGROUND/AIMS: The treatment of refractory functional dyspepsia (FD) is a challenge. Clidinium/chlordiazepoxide is a combination of antispasmodic and anxiolytic drugs that has been used as an adjunct treatment for FD in clinical practice with limited supporting evidence of efficacy. The aim of the study is to assess the efficacy and safety of clidinium/chlordiazepoxide as an adjunct treatment to a proton pump inhibitor (PPI) in refractory dyspepsia. METHODS: We performed a study of patients who met the Rome IV criteria for FD who failed to respond to PPIs. Patients were randomly assigned to groups that received clidinium/chlordiazepoxide or placebo as an add-on treatment to PPI for 4 weeks. The primary outcome was the rate of responders, which was defined as a > 50% reduction in dyspepsia symptom score after 4 weeks of treatment. The secondary outcomes were an improvement in the quality of life and the safety profile. RESULTS: Between March 2017 and February 2018, 78 patients were enrolled. The rates of responders in the clidinium/chlordiazepoxide group and placebo groups were 41.03 % and 5.13% at week 4 (P < 0.001). The clidinium/chlordiazepoxide group also showed significant improvement in overall quality of life over placebo. However, the clidinium/chlordiazepoxide group had more frequent drowsiness than the placebo group (30.27% vs 6.52%, P = 0.034). There were no major adverse events in either group. CONCLUSIONS: Clidinium/chlordiazepoxide significantly improved dyspeptic symptoms and quality of life. This combination may be used as an add-on therapy in FD patients without major adverse events.

Structural Characterization of Co-Crystals of Chlordiazepoxide with p-Aminobenzoic Acid and Lorazepam with Nicotinamide by DSC, X-Ray Diffraction, FTIR and Raman Spectroscopy.

The low water solubility of benzodiazepines seriously affects their bioavailability and, in consequence, their biological activity. Since co-crystallization has been found to be a promising way to modify undesirable properties in active pharmaceutical ingredients, the objective of this study was to prepare co-crystals of two benzodiazepines, chlordiazepoxide and lorazepam. Using different co-crystallization procedures, slurry evaporation and liquid-assisted grinding, co-crystals of chlordiazepoxide with p-aminobenzoic acid and lorazepam with nicotinamide were prepared for the first time. Confirmation that co-crystals were obtained was achieved through a comparison of the data acquired for both co-crystals using differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), Fourier-transform infrared (FTIR) and Raman spectroscopy, with comparisons acquired for the physical mixtures of both benzodiazepines and coformers. The compatibility of PXRD patterns of both benzodiazepines co-crystals with those contained in the base Powder Diffraction File (PDF-4+) suggests that new crystal structures were indeed created under the co-crystallization procedure. Single-crystal X-ray diffraction revealed that a chlordiazepoxide co-crystal with p-aminobenzoic acid and a lorazepam co-crystal with nicotinamide crystallized in the monoclinic P21/n and P21/c space group, respectively, with one molecule of benzodiazepine and one of coformer in the asymmetric unit. FTIR and Raman spectroscopy corroborated that benzodiazepine and coformer are linked by a hydrogen bond without proton exchange. Furthermore, a DSC study revealed that single endothermic DSC peaks assigned to the melting of co-crystals differ slightly depending on the co-crystallization procedures and solvent used, as well as differing from those of starting components.

Lorazepam versus chlordiazepoxide for the treatment of alcohol withdrawal syndrome and prevention of delirium tremens in general medicine ward patients.

Alcohol withdrawal syndrome (AWS) is a serious complication of abrupt alcohol cessation. Severe AWS can develop into delirium tremens (DT), which is potentially life-threatening. Lorazepam (LOR) and chlordiazepoxide (CDE) are mainstays of therapy for AWS. Current literature lacks studies comparing outcomes between the two drugs for patients who are not in a de-addiction ward specifically for withdrawal treatment. The primary objective of the study was to determine the incidence rate of DT between the groups. Of 2112 patients screened, 142 met inclusion criteria (LOR = 74, CDE = 68). Baseline characteristics were similar between groups. No significant difference in the primary outcome of DT development was observed (7% LOR, 9% CDE; p = 0.76). No significant differences in cumulative doses of scheduled LOR or CDE were observed (LOR 14.6 ± 8 mg, CDE 15.4 ± 12; p = 0.64). However, significant differences were found in the amount of "as needed" (PRN) LOR required for the two groups (LOR 3.2 ± 4 mg, CDE 6.6 ± 13 mg; p = 0.03) and the amount of scheduled plus PRN LOR required (LOR 17.7 ± 10 mg, CDE 21.9 ± 14 mg; p = 0.04). Doses are reported in LOR equivalents. There were no observed differences in duration of treatment (LOR 3.6 ± 1.3 days, CDE 3.9 ± 2.1 days; p = 0.3) or length of stay (LOR 5.28 ± 3.8 days, CDE 4.73 ± 4.2 days p = 0.4). No adverse events related to BZD were noted in either group. Hospital outcomes did not differ between the groups, but patients treated with CDE may require more adjuvant therapy to control symptoms of AWS. Both agents appear equally effective at preventing the development of DT in those patients admitted to general medicine wards.

Responses to positive and aversive stimuli in estrous female rats housed in a seminatural environment: Effects of yohimbine and chlordiazepoxide.

The behavioral effects of putative anxiolytic and anxiogenic drugs are usually evaluated in highly standardized tests. Here, we determined the effects of such drugs in rats housed in mixed sex groups in a seminatural environment. Sexually receptive female Wistar rats were treated with either the anxiolytic drug chlordiazepoxide (2 mg/kg), the anxiogenic drug yohimbine (1 mg/kg), or saline (1 ml/kg). Different emotional challenges eliciting purportedly positive affect (lavender odor, Mozart's music, chocolate flavored food) or negative affect (white noise, fox odor) were then introduced into the seminatural environment. A co-occurrence analysis revealed that music was rather aversive to the rats, as were white noise and fox odor. Lavender and chocolate exposure decreased classical indicators of fear. White noise suppressed sexual behaviors and caused avoidance of the open area. Yohimbine increased sexual receptivity during lavender exposure, decreased the latency to flee the white noise, and increased self-grooming regardless of the emotional challenge. Chlordiazepoxide was effective only during exposure to white noise, and increased the frequency of hiding alone. The modest effects of the drugs in the seminatural environment may be the result of social buffering and rats experiencing a high degree of controllability over their environment.

The contribution of contextual fear in the anxiolytic effect of chlordiazepoxide in the fear-potentiated startle test.

This study evaluated the extent to which a reduction in contextual fear contributes to the anxiolytic effect of benzodiazepines in the fear-potentiated startle response. To this end, chlordiazepoxide, an anxiolytic often used as positive control in preclinical drug studies, and zolpidem, known to have sedative properties and to be devoid of anxiolytic effects, were tested in two contexts: the same context as training had taken place and an alternative context. In addition, the level of muscle relaxation was assessed in a grip strength test. Chlordiazepoxide (2.5-10 mg/kg) decreased the fear-potentiated startle response, confirming its anxiolytic activity. In addition, it dose-dependently decreased the overall startle response in the same, but not the alternative context, and did not affect grip strength, indicating that chlordiazepoxide inhibits contextual fear in the absence of non-specific drug effects. Zolpidem (1.0-10 mg/kg) reduced the overall startle response in both contexts equally and decreased grip strength, indicating that its effects on fear-potentiated startle are due to non-specific drug effects, and not anxiolytic effects. The present findings show that chlordiazepoxide reduces contextual conditioned fear in the absence of non-specific drug effects. In addition, they show that training and testing rats in different contexts makes it possible to distinguish between cued, contextual and non-specific drug effects. As exaggerated contextual fear conditioning contributes to the fear generalization processes implicated in pathological anxiety, focus in screening of anxiolytic effects could be directed more towards the suppression of contextual fear and, therefore, this approach would be a valuable addition to standard preclinical screening.

No effect of sex and estrous cycle on the fear potentiated startle response in rats.

The prevalence of anxiety disorders is higher in women than in men. Yet preclinical studies on anxiety are mostly performed in male subjects. This may have limited our understanding of mechanisms contributing to anxiety disorders. Since fear conditioning is considered an important factor in the etiology of anxiety disorders, the present study aimed to investigate the effect of sex and estrous cycle on conditioned fear and the anxiolytic effect of benzodiazepines in rats. We measured the fear-potentiated startle response in male and female rats during different estrous cycle stages and performed a replication study in a separate cohort. In addition, we assessed the response to diazepam (0-3.0 mg/kg IP) and chlordiazepoxide (0-10 mg/kg IP) in male and female rats in proestrous/estrous and diestrous stage. Our results showed that there were no sex differences in the expression of fear-potentiated startle. The estrous cycle also did not affect the fear-potentiated startle response. In addition, male and female rats did not differ in their fear-potentiated startle response following treatment with either diazepam or chlordiazepoxide. In conclusion, the current study shows that male and female rats do not differ in their conditioned fear response and the responsiveness to benzodiazepines. The results further indicate that conditioned fear-related processes are not affected by gonadal hormone fluctuations in this paradigm. These findings may suggest that the higher prevalence of anxiety disorders in women more likely results from differences in responding to previous experiences or differences in other predisposing factors, rather than differences in conditioned fear per se.

Vicarious Social Defeat Stress Induces Depression-Related Outcomes in Female Mice.

BACKGROUND: Stress is a prevailing risk factor for mood-related illnesses, wherein women represent the majority of those affected by major depression. Despite the growing literature suggesting that affective disorders can arise after a traumatic event is vicariously experienced, this relationship remains understudied in female subjects at the preclinical level. Thus, the objective of the current investigation was to examine whether exposure to emotional and/or psychological stress (ES) mediates depression-related outcomes in female mice. METHODS: Female C57BL/6 mice (8 weeks old, null parity) vicariously experienced the defeat bout of a male conspecific, by a male CD1 aggressor, for 10 consecutive days. Twenty-four hours after the last stress exposure, female mice were tested in the social interaction, sucrose preference, tail suspension, or elevated plus maze tests. Furthermore, we examined whether ketamine and chlordiazepoxide, pharmacological agents used to treat mood-related disorders in the clinical population, would reverse the ES-induced social dysfunction. RESULTS: When compared with control mice, female mice exposed to ES displayed decreased social behavior and preference for sucrose, along with increased immobility in the tail suspension test. Also, they displayed higher levels of blood serum corticosterone, as well as decreased body weight. Lastly, the ES-induced avoidance-like phenotype was ameliorated by both ketamine and chlordiazepoxide. CONCLUSIONS: Our data indicate that female mice exposed to ES display a behavioral and physiologic profile that mimics symptoms of depression in the clinical population. As such, this experimental model may be adopted to examine vicarious stress-induced mood-related disorders, as well as pharmacological antidepressant response, in a sex-specific manner.

Proximity as a predictor of social behavior in rats.

BACKGROUND: In studies that measure social behavior of a freely interacting pair rats social behavior of one rat is strongly influenced by the behavior of the other. This prevents evaluating social behavior of one single rat. NEW METHOD: We assessed the motivation to interact socially in a modified open-field, by measuring the time a rat attempted to interact with a co-specific separated by a grid in a birdcage outside of the apparatus. We propose time in front of the birdcage is an indicator of social behavior. RESULTS: We showed that the focal rat allocates more time in front of the birdcage, interacting with another rat through the grid. Also, that the presence of the other rat that attracts the focal rat. Habituation to the apparatus, repeated testing and illumination condition did not alter the proximity measures of rats. Finally, treatment with chlordiazepoxide (3.0mg/kg) either increased the time spent in front of the cage by males and females or (5.6mg/kg) increased the proximity measure of females. COMPARING WITH EXISTING METHOD: Our method prevents partners from influencing the target rat's social behavior; existing methods do not. Also, it is more sensitive to the effect of chlordiazepoxide than the broadly used method proposed by File and Hyde (1978). CONCLUSIONS: Proximity is an advantageous measure: it allows the assessment of only one focal animal without the interference of a partner; it is simple to take; it requires little interpretation skills or training from the experimenter, no special equipment or conditions.