Ultrasonic Distress Vocalizations Research Articles

Moderate ethanol exposure during early ontogeny of the rat alters respiratory plasticity, ultrasonic distress vocalizations, increases brain catalase activity, and acetaldehyde-mediated ethanol intake.

Early ontogeny of the rat (late gestation and postnatal first week) is a sensitive period to ethanol's positive reinforcing effects and its detrimental effects on respiratory plasticity. Recent studies show that acetaldehyde, the first ethanol metabolite, plays a key role in the modulation of ethanol motivational effects. Ethanol brain metabolization into acetaldehyde via the catalase system appears critical in modulating ethanol positive reinforcing consequences. Catalase system activity peak levels occur early in the ontogeny. Yet, the role of ethanol-derived acetaldehyde during the late gestational period on respiration response, ultrasonic vocalizations (USVs), and ethanol intake during the first week of the rat remains poorly explored. In the present study, pregnant rats were given a subcutaneous injection of an acetaldehyde-sequestering agent (D-penicillamine, 50 mg/kg) or saline (0.9% NaCl), 30 min prior to an intragastric administration of ethanol (2.0 g/kg) or water (vehicle) on gestational days 17-20. Respiration rates (breaths/min) and apneic episodes in a whole-body plethysmograph were registered on postnatal days (PDs) 2 and 4, while simultaneously pups received milk or ethanol infusions for 40-min in an artificial lactation test. Each intake test was followed by a 5-min long USVs emission record. On PD 8, immediately after pups completed a 15-min ethanol intake test, brain samples were collected and kept frozen for catalase activity determination. Results indicated that a moderate experience with ethanol during the late gestational period disrupted breathing plasticity, increased ethanol intake, as well brain catalase activity. Animals postnatally exposed to ethanol increased their ethanol intake and exerted differential affective reactions on USVs and apneic episodes depending on whether the experience with ethanol occur prenatal or postnatally. Under the present experimental conditions, we failed to observe, a clear role of acetaldehyde mediating ethanol's effects on respiratory plasticity or affective states, nevertheless gestational acetaldehyde was of crucial importance in determining subsequent ethanol intake affinity. As a whole, results emphasize the importance of considering the participation of acetaldehyde in fetal programming processes derived from a brief moderate ethanol experience early in development, which in turn, argues against "safe or harmless" ethanol levels of exposure.

Models of Anxiety: Ultrasonic Vocalizations of Isolated Rat Pups

Described in this unit is the ultrasonic distress vocalization test in rat pups. This test is a reliable method for detecting anxiolytic properties of test compounds. In this test, ultrasonic vocalizations (30 to 50 kHz) are elicited by separating rat pups of 9 to 11 days of age from their mother and littermates for a brief period of time. The test can be performed under two different stress conditions. Pups are placed in isolation in either a warm (37°C) or cold (18°C) environment for 5 min. The total number and duration of ultrasonic calls emitted by the pups during this period is used as an index of anxiety. Established anxiolytic compounds, including benzodiazepines, serotonin(1A) receptor agonists, and selective serotonin reuptake inhibitors (SSRIs), consistently reduce the number and cumulative duration of these ultrasonic distress vocalizations.

Designing mouse behavioral tasks relevant to autistic‐like behaviors

The importance of genetic factors in autism has prompted the development of mutant mouse models to advance our understanding of biological mechanisms underlying autistic behaviors. Mouse models of human neuropsychiatric diseases are designed to optimize (1) face validity, i.e., resemblance to the human symptoms; (2) construct validity, i.e., similarity to the underlying causes of the disease; and (3) predictive validity, i.e., expected responses to treatments that are effective in the human disease. There is a growing need for mouse behavioral tasks with all three types of validity for modeling the symptoms of autism. We are in the process of designing a set of tasks with face validity for the defining features of autism: deficits in appropriate reciprocal social interactions, deficits in verbal social communication, and high levels of ritualistic repetitive behaviors. Social approach is tested in an automated three-chambered apparatus that offers the subject a choice between a familiar environment, a novel environment, and a novel environment containing a stranger mouse. Preference for social novelty is tested in the same apparatus, with a choice between the start chamber, the chamber containing a familiar mouse, and the chamber containing a stranger mouse. Social communication is evaluated by measuring the ultrasonic distress vocalizations emitted by infant mouse pups and the parental response of retrieving the pup to the nest. Resistance to change in ritualistic repetitive behaviors is modeled by forcing a change in habit, including reversal of the spatial location of a reinforcer in a T-maze task and in the Morris water maze. Mouse behavioral tasks that may model additional features of autism are discussed, including tasks relevant to anxiety, seizures, sleep disturbances, and sensory hypersensitivity. Applications of these tests include (1) behavioral phenotyping of transgenic and knockout mice with mutations in genes relevant to autism, (2) characterization of mutant mice derived from random chemical mutagenesis, (3) DNA microarray analyses of genes in inbred strains of mice that differ in social interaction, social communication and resistance to change in habit, and (4) evaluation of proposed therapeutics for the treatment of autism.

Individual housing during the play period results in changed responses to and consequences of a psychosocial stress situation in rats.

In the present study, the consequences of individual rearing during the play period on adult responses to aggression were investigated in a complex social setting. In a group of either socially or individually reared rats, an aggressor was repeatedly introduced. Separate control groups of individually and socially reared rats were not exposed to an aggressor. To allow an interpretation of the altered reactivity to aggression in terms of (in)efficient or (in)adequate behavior, not only the responses in the presence of the aggressor but also the consequences of the altered reactivity on subsequent behavior in the absence of the aggressor were observed. We demonstrated that a higher number of injuries, more agitation of the aggressor, and more ultrasonic distress vocalizations accompanied the altered responses of individually reared rats in the presence of the aggressor. In the absence of the aggressor, individually reared rats displayed less social stress-reducing behaviors (play and social grooming) than socially reared rats. It was concluded that individually reared rats display a less adequate response to aggression in this social context.

Fetal and neonatal exposure to trimethylolpropane phosphate alters rat social behavior and emotional responsivity.

The proconvulsant compound trimethylolpropane phosphate (TMPP) was evaluated for its effects on motor, social, and emotional behaviors. Long Evans rats were treated prenatally for 13 days and/or neonatally for 10 days. Behavioral tests were performed during treatment and several days after treatment. Beginning on gestation day 9, and continuing for 13 days, 20 dams received once daily i.p. injections. Half were treated with distilled water, the other 10 received 0.2 mg TMPP/kg body weight. No external malformations were observed in the live-born offspring of TMPP- or vehicle-exposed dams. On postnatal day 3 one-half the pups were cross-fostered to dams that had the opposite treatment as their biological mothers. Also on postnatal day 3, pups were divided into two groups, one receiving injections of distilled water, the other receiving injections of 0.2 mg TMPP/kg body weight. Ten daily injections were administered i.p., beginning postnatal day 3. Motor behaviors were evaluated in step-down and paw lift tasks and no group differences were found. At 18 days of age, one half the pups were separated from the dam and their littermates. The other half of the pups continued to be housed with the dam and remaining littermates until postnatal day 50. Social interaction was measured in juvenile play and adult social investigation. Emotional responsivity was assessed in open field activity, elevated plus-maze exploration, and ultrasonic distress vocalizations. Complex interactions were found for measures of social interaction and emotional responsivity related to drug treatment, housing condition, and sex. Due to the observed sex differences. it is hypothesized that the action of TMPP may involve a change in the hormonal systems that control the differentiation of related sex-typical behaviors.

Conditioned ultrasonic distress vocalizations in adult male rats as a behavioural paradigm for screening anti-panic drugs

Rats may produce ultrasonic vocalizations (USV) in threatening situations. USV of adult male rats in association with aversive stimulation was evaluated as a screening method for anxiolytic drugs. The triazolobenzodiazepine alprazolam, the 5-HT uptake inhibitors fluvoxamine and clomipramine, the mixed 5-HT/NA uptake inhibitor imipramine, the full 5-HT1A receptor agonists 8-OH-DPAT and flesinoxan, the partial 5-HT1A receptor agonists buspirone, ipsapirone and BMY 7378, the alpha 2-adrenoceptor agonist clonidine and the alpha 2-adrenoceptor antagonist yohimbine reduced conditioned USV. The classical benzodiazepines (BZD) diazepam and chlordiazepoxide were ineffective or had a very low potency to decrease USV. The partial BZD receptor agonists bretazenil, alpidem and zolpidem, the BZD receptor antagonist flumazenil, the NA uptake inhibitors desipramine and maprotiline, and the 5-HT3 receptor antagonist ondansetron had no effect on conditioned USV. The dopamine-D2 receptor antagonist haloperidol reduced USV at a very high dose. In separate experiments the effects of these drugs on locomotor activity were assessed. There was, however, no direct relationship between effects on motor behaviour and USV. In conclusion, the sensitivity of conditioned USV to 5-HT uptake inhibitors and alprazolam versus the insensitivity to classical benzodiazepines and NA uptake inhibitors provides a very interesting profile, which closely resembles the psychopharmacology of panic disorder. Also the face validity of conditioned USV towards situational panic attacks is high. We therefore propose conditioned USV in adult male rats as a novel behavioural paradigm to screen for anti-panic drugs.

Aversive properties of the kappa opioid agonist U50,488 in the week-old rat pup.

mu Opioids have been shown to produce analgesia and to be reinforcing during the first week of life in the rat. kappa Opioids also have analgesic actions in both the infant and adult, but can be aversive in the mature animal. We examined the aversive effects of the kappa opioid agonist U50,488 during the first postnatal week in the rat pup in three ways. In the first experiment, U50,488, injected peripherally (1.0-30.0 mg/kg), was paired with an odor and pups were tested 8 h later for positional preference for avoidance of that odor. This task is similar to conditioned preference/aversion tests used with adult animals. Both 3- and 7-day-old pups learned to avoid the odor adulterated side at the two higher doses. When exposed to odors previously associated with U50,488, pups at both ages decreased locomotor activity. In a second experiment, acute treatment with U50,488 increased ultrasonic distress vocalizations (USV) equally at 3 and 7 days of age, increased locomotor activity, and decreased rectal temperature. Neither of the latter two effects was correlated with the increase in USV production. The third experiment showed that conditioned odor cues increased USV 8 h later in 3- and 7-day-old pups at 1.0-10.0 mg/kg without changes in activity or rectal temperature. The results from these studies suggest that U50,488 can produce aversions in the neonatal rat pup as it does in the adult.

Automatic quantification of withdrawal from 5-day diazepam in rats: ultrasonic distress vocalizations and hyperreflexia to acoustic startle stimuli.

The purpose of the present work was to develop an objective and precise method to quantify withdrawal responses from anxiolytics relying on ethologically valid responses. Behavioral effects of diazepam withdrawal in rats are automatically measured that appear to correspond to clinically relevant disturbances in affective and sensory-motor functions. Ultrasonic vocalizations and startle reflexes in response to acoustic stimuli were measured as indices of withdrawal 24 h after 5 days of 2.5, 5 or 10 mg/kg diazepam, b.i.d., IP in male Long-Evans rats. About 60% of male rats emit 22-26 kHz ultrasonic calls when exposed to acoustic startle stimuli (18 presentations, 9 at 105 dB and 9 at 115 dB, each 30 s apart on average). Diazepam-withdrawn rats exhibited startle responses with larger maximal and average amplitude and emitted more frequent 22-26 kHz ultrasonic vocalizations than vehicle-treated control animals. The magnitude of the withdrawal changes in ultrasonic calls and in startle reflex amplitude increased significantly already at the low 2.5 mg/kg diazepam dose in spite of considerable individual variability. The increased ultrasound rates during diazepam withdrawal contrast with the suppressive effects of acutely administered diazepam in drug-naive rats. The current methodology offers the opportunity to more adequately characterize withdrawal from anxiolytic substances in a quantitative, objective and automated manner.

D-Amino acids influence ultrasonic calling in mice pups: Effects of d-phenylalanine and d-leucine

6-day-old mice pups were injected with d-amino acids ( d-phenyl-alanine + d-leucine ), and their ultrasonic distress vocalizations were measured. d-Amino acids, which exert opioid-like effects, reduce the number of ultrasonic calls without affecting the activity of the pups. This effect is reversed by naloxone, an opioid antagonist. The role of endogenous opioids in modulating early attachment is discussed.

Inhibition of ultrasonic distress vocalizations in rat pups by chlordiazepoxide and diazepam

AbstractWistar rat pups emit ultrasonic distress cries when placed on a cold plate or when held by the tail. More sounds were induced by tail holding than by placing on the cold plate, but in both cases the number emitted was relatively constant from 7 to 13 days of age. Chlordiazepoxide and diazepam inhibited the sounds, and their activity was only associated with sedation and muscle relaxation at higher doses. The muscle relaxant mephenesin had little effect. Prazosin induced sedation and hypothermia and inhibited sounds induced by tail holding more than those on the cold plate. Clonidine induced hypothermia and weak sedation and increased sound emission weakly for the tail holding response but markedly for responses on the plate. This separation of responses may result from potentiation of responses on the plate by drug‐induced hypothermia. Although sedative effects result in decreased ultrasounds, the benzodiazepines continue to reduce sounds at doses showing little or no sedation. It is suggested that the benzodiazepines may reduce the sound via their anxiolytic action.

Do pup ultrasonic cries provoke prolactin secretion in lactating rats?

Marked prolactin (PRL) secretion in response to the ultrasonic distress vocalizations of rat pups in lactating dams deprived of their pups for 6 hr was reported by others. In two experiments, this phenomenon could not be confirmed under our testing conditions at either 1 or 2 weeks postpartum, although behavioral responses to the ultrasounds were noted. In addition, suckling-induced PRL secretion did not differ consistently as a function of the tape recording (pup ultrasounds, 45 kHz artificially produced ultrasounds, or blank tape) heard prior to the return of pups. The functional significance of rat pup ultrasounds is considered.