Direct and long-lasting effects elicited by repeated drug administration on 50-kHz ultrasonic vocalizations are regulated differently: Implications for the study of the affective properties of drugs of abuse

Several studies suggest that 50-kHz ultrasonic vocalizations (USVs) may indicate a positive affective state in rats, and these vocalizations are increasingly being used to investigate the properties of psychoactive drugs. Previous studies, however, have focused on dopaminergic psychostimulants and morphine, whereas little is known about how other drugs modulate 50-kHz USVs. To further elucidate the neuropharmacology of 50-kHz USVs, the present study characterized the direct and long-lasting effects of different drugs of abuse, by measuring the number of 50-kHz USVs and their 'trill' subtype emitted by adult male rats. Rats received repeated administrations of amphetamine (2 mg/kg, i.p.), 3,4-methylenedioxymethamphetamine (MDMA, 7.5 mg/kg, i.p.), morphine (7.5 mg/kg, s.c.), or nicotine (0.4 mg/kg, s.c.), on either consecutive or alternate days (five administrations in total) in a novel environment. Seven days later, rats were re-exposed to the drug-paired environment, subjected to USVs recording, and then challenged with the same drug. Finally, 7 d after the challenge, rats were repeatedly exposed to the drug-paired environment and vocalizations were measured. Amphetamine was the only drug to stimulate 50-kHz USVs and 'trill' subtype emission during administration and challenge. Conversely, all rats emitted 50-kHz USVs when re-exposed to the test cage, and this effect was most marked in morphine-treated rats, and less evident in nicotine-treated rats. This study demonstrates that the direct and long-lasting effects of drugs on 50-kHz USVs are regulated differently, providing a better understanding of the usefulness of these vocalizations in the study of psychoactive drugs

Involvement of Glutamate NMDA Receptors in the Acute, Long-Term, and Conditioned Effects of Amphetamine on Rat 50kHz Ultrasonic Vocalizations

BACKGROUND: Rats emit 50kHz ultrasonic vocalizations (USVs) in response to either natural or pharmacological pleasurable stimuli, and these USVs have emerged as a new behavioral measure for investigating the motivational properties of drugs. Earlier studies have indicated that activation of the dopaminergic system is critically involved in 50kHz USV emissions. However, evidence also exists that non-dopaminergic neurotransmitters participate in this behavioral response. METHODS:To ascertain whether glutamate transmission plays a role in 50kHz USV emissions stimulated by amphetamine, rats received five amphetamine (1-2mg/kg, i.p.) administrations on alternate days in a test cage, either alone or combined with the glutamate N-methyl-D-aspartate receptor antagonist MK-801 (0.1-0.5mg/kg, i.p.). Seven days after treatment discontinuation, rats were re-exposed to the test cage to assess drug conditioning, and afterwards received a drug challenge. USVs and locomotor activity were evaluated, along with immunofluorescence for Zif-268 in various brain regions and spontaneous alternation in a Y maze. RESULTS:Amphetamine-treated rats displayed higher 50kHz USV emissions and locomotor activity than vehicle-treated rats, and emitted conditioned vocalizations on test cage re-exposure. Rats co-administered amphetamine and MK-801 displayed lower and dose-dependent 50kHz USV emissions, but not lower locomotor activity, during repeated treatment and challenge, and scarce conditioned vocalization compared with amphetamine-treated rats. These effects were associated with lower levels of Zif-268 after amphetamine challenge and spontaneous alternation deficits. CONCLUSIONS: These results indicate that glutamate transmission participates in the acute, long-term, and conditioned effects of amphetamine on 50kHz USVs, possibly by influencing amphetamine-induced long-term neuronal changes and/or amphetamine-associated memories

Association between novel object recognition/spontaneous alternation behavior and emission of ultrasonic vocalizations in rats: Possible relevance to the study of memory

Rats emit ultrasonic vocalizations (USVs) in situations with emotional valence, and USVs have also been proposed as a marker for memories conditioned to those situations. This study investigated whether USV emissions can predict and/or be associated with the behavior of rats in tests that evaluate unconditioned memory. To this end, rats were subjected to “tickling”, a procedure of heterospecific play that has emotional valence and elicits the emission of USVs, and afterwards evaluated in the novel object recognition test (NOR) and in the single trial continuous spontaneous alternation behavior (SAB) test in a Y-maze. The number of 22-kHz USVs (aversive) and 50-kHz USVs (appetitive) emitted in response to tickling and during NOR and SAB tests were scored, and the correlations among them and with rats’ behavior evaluated. Rats emitted 50-kHz USVs, but not 22-kHz USVs, during the NOR and SAB tests, and such calling behavior was not linked with the behavioral readouts indicative of memory function in either test. However, rats that prevalently emitted 22-kHz USVs in response to tickling displayed an impaired NOR performance. These findings suggest that measuring the emission of USVs could be of interest in studies of unconditioned memory, at least with regard to 22-kHz USVs

Comment on 'Nucleation of 3He-B from the A Phase: A Cosmic-Ray Effect?'

A comment to the article by Leggett, A. J.Peer reviewe

Mouse and rat ultrasonic vocalizations in neuroscience and neuropharmacology: State of the art and future applications

Mice and rats emit ultrasonic vocalizations (USVs), which may express their arousal and emotional states, to communicate with each other. There is continued scientific effort to better understand the functions of USVs as a central element of the rodent behavioral repertoire. However, studying USVs is not only important because of their ethological relevance, but also because they are widely applied as a behavioral readout in various fields of biomedical research. In mice and rats, a large number of experimental models of brain disorders exist and studying the emission of USVs in these models can provide valuable information about the health status of the animals and the effectiveness of possible interventions, both environmental and pharmacological. This review (i) provides an updated overview of the contexts in which ultrasonic calling behaviour of mice and rats has particularly high translational value, and (ii) gives some examples of novel approaches and tools used for the analysis of USVs in mice and rats, combining qualitative and quantitative methods. The relevance of age and sex differences as well as the importance of longitudinal evaluations of calling and non-calling behaviour is also discussed. Finally, the importance of assessing the communicative impact of USVs in the receiver, that is, through playback studies, is highlighted

Changes in parents' psychotropic medication use following child's cancer diagnosis : A fixed-effects register-study in Finland

Background Symptoms of depression and anxiety are elevated among parents of children with cancer. However, knowledge of parents' psychotropic medication use following child's cancer diagnosis is scarce. Methods We use longitudinal Finnish register data on 3266 mothers and 2687 fathers whose child (aged 0-19) was diagnosed with cancer during 2000-2016. We record mothers' and fathers' psychotropic medication use (at least one annual purchase of anxiolytics, hypnotics, sedatives, or antidepressants) 5 years before and after the child's diagnosis and assess within-individual changes in medication use by time since diagnosis, cancer type, child's age, presence of siblings, and parent's living arrangements and education using linear probability models with the individual fixed-effects estimator. The fixed-effects models compare each parent's annual probability of psychotropic medication use after diagnosis to their annual probability of medication use during the 5-year period before the diagnosis. Results Psychotropic medication use was more common among mothers than fathers already before the child's diagnosis, 11.2% versus 7.3%. Immediately after diagnosis, psychotropic medication use increased by 6.0 (95% CI 4.8-7.2) percentage points among mothers and by 3.2 (CI 2.1-4.2) percentage points among fathers. Among fathers, medication use returned to pre-diagnosis level by the second year, except among those whose child was diagnosed with acute lymphoblastic leukemia or lymphoblastic lymphoma. Among mothers of children with a central nervous system cancer, medication use remained persistently elevated during the 5-year follow-up. For mothers with other under-aged children or whose diagnosed child was younger than 10 years, the return to pre-diagnosis level was also slow. Conclusions Having a child with cancer clearly increases parents' psychotropic medication use. The increase is smaller and more short-lived among fathers, but among mothers its duration depends on both cancer type and family characteristics. Our results suggest that an increased care burden poses particular strain to the long-term mental well-being of mothers.Peer reviewe

Life Fertility Tables of Piophila casei L. (Diptera: Piophilidae) Reared at Five Different Temperatures

Abstract Piophila casei L. or cheese skipper is a well-known fly with a controversial role: it is considered harmful in the food industries but important in nature as a detritivore and useful for studies in forensic entomology. The temperature response of P. casei was studied at five constant temperatures: 15, 19, 25, 28, and 32°C. The lowest mortality percentage of eggs was recorded at 15°C and the highest at 32°C. Conversely, less mortality was observed for maggots at higher temperatures. The developmental time from first instar to adult decreased with temperature reaching the lowest value at 32°C (13.7 d). Adult longevity was strongly affected by temperature, decreasing from 20.5 d at 15°C to 6.6 d at 32°C. Mean total fecundity per female was higher at 25°C and lower at 15 and 19°C, whereas the best performance in mean daily total fecundity per female was recorded at 32°C. Male longevity followed a similar trend to the one observed for females. The net reproductive rate (R0) was greatest at 25°C, where..

Financial attractiveness of wood production in smallholder plantations of Central Vietnam in the context of developing carbon markets

In Vietnam, fast-growing Acacia hybrid dominates commercial smallholdings and is largely managed in short rotations for pulpwood. However, increasing demand for logwood implies growing Acacia hybrid in longer rotations. One way of encouraging smallholders to prolong the rotation would be payments for aboveground carbon storage. Thus, this study evaluated the financial attractiveness of shifting from pulpwood to logwood production, with and without hypothetical carbon payments of $5,$10 and $20 tCO(2)e ha(-1). The data were drawn from smallholder interviews, a plantation inventory and a market study. The growth models for a 5-year pulpwood regime and various logwood regimes used for financial modelling were developed in CO2FIX simulation software. With a financially optimal rotation length of 9-10 years, the study finds that growing Acacia hybrid for logwood is much more profitable than growing it for pulpwood. However, due to thinning in logwood regime, a financially optimal logwood regime stores only 15-16% more carbon than a 5-year pulpwood regime. Consequently, carbon payments at any of the three price levels would not shift the financially optimal rotation length. The study concluded that carbon payments alone are unlikely to be an effective means to encourage smallholders in central Vietnam to prolong the rotation.Peer reviewe