Extinction Period Research Articles

Independent rediploidization masks shared whole genome duplication in the sturgeon-paddlefish ancestor

Whole genome duplication (WGD) is a dramatic evolutionary event generating many new genes and which may play a role in survival through mass extinctions. Paddlefish and sturgeon are sister lineages that both show genomic evidence for ancient WGD. Until now this has been interpreted as two independent WGD events due to a preponderance of duplicate genes with independent histories. Here we show that although there is indeed a plurality of apparently independent gene duplications, these derive from a shared genome duplication event occurring well over 200 million years ago, likely close to the Permian-Triassic mass extinction period. This was followed by a prolonged process of reversion to stable diploid inheritance (rediploidization), that may have promoted survival during the Triassic-Jurassic mass extinction. We show that the sharing of this WGD is masked by the fact that paddlefish and sturgeon lineage divergence occurred before rediploidization had proceeded even half-way. Thus, for most genes the resolution to diploidy was lineage-specific. Because genes are only truly duplicated once diploid inheritance is established, the paddlefish and sturgeon genomes are thus a mosaic of shared and non-shared gene duplications resulting from a shared genome duplication event.

VU0155041, a positive allosteric modulator of mGluR4, in the nucleus accumbens facilitates extinction and inhibits the reinstatement of morphine-induced conditioned place preference in male rats

Nucleus accumbens (NAc) neurons appear to be at the hub of the reward circuit. New evidence suggests that the behavioural effects of morphine substances may be significantly regulated by glutamate-mediated transmission, notably by metabotropic glutamate (mGlu) receptors. Here, we examined the hypothesis that the mGlu4 receptor within that NAc has a role in the extinction and reinstatement of morphine-induced conditioned place preference (CPP). The animals received bilaterally microinjections of VU0155041, a positive allosteric modulator (PAM) and partial agonist of mGlu4 receptor, into the NAc. In Experiment 1, the rats received VU0155041 (10, 30 and 50 μg/0.5 μL) during the extinction period. In Experiment 2, the CPP extinguished rats received VU0155041 (10, 30 and 50 μg/0.5 μL) five minutes prior to the administration of morphine (1 mg/kg) in order to reinstate the extinguished CPP. The results showed that the intra-accumbal administration of VU0155041 reduced the extinction period of CPP. Furthermore, the administration of VU0155041 into the NAc dose-dependently inhibited the reinstatement of CPP. The findings suggested that the mGluR4 in the NAc facilitates the extinction and inhibits the reinstatement of the morphine-induced CPP, which could be mediated by an increase in the release of extracellular glutamate.

Distinct suppressing effects of deep brain stimulation in the orbitofrontal cortex on the development, extinction, and reinstatement of methamphetamine-seeking behaviors

AimsThe orbitofrontal cortex (OFC) is implicated in compulsive drug-seeking and relapse, the characteristics that result in addiction treatment failure. Structural and functional impairments within the OFC have been detected in many substance use disorders (SUDs). Deep brain stimulation (DBS) is proposed as a promising therapeutic option in treating SUDs. Therefore, the present study aimed to investigate the potential efficacy of DBS application on the various stages of the methamphetamine-conditioned place preference (CPP) paradigm in rats. Main methodsElectrodes were implanted unilaterally in the rat's right OFC. DBS in the form of high- or low-frequency stimulation (HFS: 130 Hz, LFS: 13 Hz) was applied during the 5-day conditioning phase (a daily 30-min session) or extinction period (30-min session, daily, ten days) of methamphetamine-induced CPP in two separate sets of experiments. Following extinction, place preference was reinstated by injecting a priming dose of methamphetamine (0.25 mg/kg). Key findingsThe HFS and LFS significantly decreased the methamphetamine place preference when applied over the conditioning period. In the extinction experiment, only HFS could remarkably accelerate the extinction of reward-context associations and even reduce the methamphetamine-induced reinstatement of seeking behaviors. SignificanceConclusively, DBS administration in the OFC demonstrated some positive results, including suppressing effects on the development, maintenance, and relapse of methamphetamine-seeking behavior. These findings encourage conducting more preclinical studies to strongly suggest a wide range of DBS applications in cortical areas such as OFC as an efficient treatment modality for psychostimulant use disorder.

Evaluation of the effect of mesenchymal stem cells injection in the nucleus accumbens on the morphine reinstatement behavior in a conditioned place preference model in Wistar rat: Expression changes of NMDA receptor subunits and NT-3

Mesenchymal stem cells (MSCs) have been recently shown to improve functional recovery in animal models of CNS disorders and are currently being examined in clinical studies for sclerosis, stroke, and CNS lesions. The activation of endogenous CNS protection and repair mechanisms is unclear. MSC-based approaches are considered a new potential target for neurodegenerative disorders. This study was designed to discover the effect of MSCs injection in the nucleus accumbens (NAc) on the reinstatement of behavior in morphine-induced conditioned place preference (CPP) in male rats. The CPP was induced via intra-peritoneal (i.p.) morphine injection (5 mg/kg) for three consecutive days. After being tested for CPP induction, animals received MSCs or culture medium (DMEM F-12) in their NAc using stereotaxic surgery. Following extinction, a priming dose of morphine (2 mg/kg) was administered to induce reinstatement. Expression of GluN1, GluN2A, and GluN2B subunits of the NMDA receptor and the NT-3 gene in the NAc was assessed on the last day of extinction and following CPP reinstatement. The results showed that local injection of MSCs attenuated reinstatement after receiving a priming dose of morphine, and also shortened the period of CPP extinction. The mRNA expression of the NT-3 gene in the group receiving MSCs was increased compared to control animals, as was observed for GluN1 and GluN2B, but not GluN2A. It is concluded that intra-NAc injection of MSCs may facilitate morphine extinction and alleviate reinstatement behavior which may be via expression changes in NMDA receptor subunits and NT-3 gene.

A wide range of Deep Brain Stimulation of the nucleus accumbens shell time independently reduces the extinction period and prevents the reinstatement of methamphetamine-seeking behavior in rats

Methamphetamine (METH) addiction is a significant public health issue, and standard medical therapies are often not curative. Deep Brain Stimulation (DBS) has recently shown the potential to cure addiction by modulating neural activity in specific brain circuits. Recent studies have revealed that the nucleus accumbens shell (NAcSh) could serve as a promising target in treating addiction. Therefore, the present study aimed to investigate the therapeutic effects of NAcSh high- or low-frequency stimulation (HFS or LFS) in the different time points of application on the extinction and reinstatement of the METH-conditioned place preference (CPP). LFS or HFS (10 or 130 Hz, 150–200 μA, 100 μs) was delivered to the NAcSh for 30 min non-simultaneous (in a distinct non-drug environment) or simultaneous (in a drug-paired context) of the drug-free extinction sessions. The obtained results showed that both non-simultaneous and simultaneous treatments by HFS and LFS notably reduced the extinction period of METH-induced CPP. Furthermore, the data indicated that both non-synchronous and synchronous HFS prevented METH-primed reinstatement, while only the LFS synchronized group could block the reinstatement of METH-seeking behavior. The results also demonstrated that HFS was more effective than LFS in attenuating METH-primed reinstatement, and applying HFS synchronous was significantly more effective than HFS non-synchronous in reducing the relapse of drug-seeking. In conclusion, the current study's results suggest that DBS of the NAcSh in a wide range of frequencies (LFS and HFS) could affect addiction-related behaviors. However, it should be considered that the frequency and timing of DBS administration are among the critical determining factors.

Voluntary alcohol consumption during distinct phases of adolescence differentially alters adult fear acquisition, extinction and renewal in male and female rats

Alcohol use during adolescence coincides with elevated risks of stress-related impairment in adults, particularly via disrupted developmental trajectories of vulnerable corticolimbic and mesolimbic systems involved in fear processing. Prior work has investigated the impact of binge-like alcohol consumption on adult fear and stress, but less is known about whether voluntarily consumed alcohol imparts differential effects based on adolescence phases and biological sex. Here, adolescent male and female Long Evans rats were granted daily access to alcohol (15%) during either early (Early-EtOH; P25-45) or late adolescence (Late-EtOH; P45-55) using a modified drinking-in-the-dark design. Upon adulthood (P75-80), rats were exposed to a three-context (ABC) fear renewal procedure. We found that male and female Early-EtOH rats showed faster acquisition of fear but less freezing during early phases of extinction and throughout fear renewal. In the extinction period specifically, Early-EtOH rats showed normal levels of freezing in the presence of fear-associated cues, but abnormally low freezing immediately after cue offset, suggesting a key disruption in contextual processing and/or novelty seeking brought by early adolescent binge consumption. While the effects of alcohol were most pronounced in the Early-EtOH rats (particularly in females), Late-EtOH rats displayed some changes in fear behavior including slower fear acquisition, faster extinction, and reduced renewal compared with controls, but primarily in males. Our results suggest that early adolescence in males and females and, to a lesser extent, late adolescence in males is a particularly vulnerable period wherein alcohol use can promote stress-related dysfunction in adulthood. Furthermore, our results provide multiple bases for future research focused on developmental correlates of alcohol mediated disruption in the brain.

Distinct roles for orexin-1 and orexin-2 receptors in the dentate gyrus of the hippocampus in the methamphetamine-seeking behavior in the rats

Because of the relapsing properties of psychostimulants such as methamphetamine (Meth), there is no established pharmacotherapy for Meth addiction. The orexinergic system is a promising target for treating psychostimulant use disorders and relapse. However, to the best of our knowledge, no investigation regarding the role of orexin receptors in the dentate gyrus (DG) region of the hippocampus has been conducted in the extinction and reinstatement of Meth-seeking behavior. Two stainless-steel guide cannulae were bilaterally implanted into the DG of the rats' brains. The unbiased conditioned place preference (CPP) procedure was conducted to induce Meth conditioning. Following the five days Meth injections (1 mg/kg; sc), animals received intra-DG microinjection of SB334867 or TCS OX2 29, as orexin 1 (OX1) or orexin 2 (OX2) receptor antagonists, respectively (without Meth administration) during extinction phase to elucidate the role of orexin receptors in the latency of the extinction period in the Meth-conditioned rats. To evaluate the role of orexin receptors in the DG region in the reinstatement of Meth-seeking behavior, the extinguished rats received SB334867 or TCS OX2 29 before injecting a priming dose of Meth (0.25 mg/kg; sc). The results indicated two distinct roles for the OX1 and OX2 receptors in the DG region. TCS OX2 29 attenuated the extinction latency, and SB334867 considerably reduced the reinstatement of Meth-seeking behavior in this region. Therefore, the DG region's orexinergic system might be a potential therapeutic target for psychostimulant use disorders.

Characteristics of Calcium Isotopes at Different Water Depths and Their Palaeoenvironmental Significance for Carbonate Rocks of the Permian-Triassic Boundary in Chibi, Southern China

Calcium isotopes of carbonate rocks can trace calcium cycles and record changes in the marine environment. As published calcium isotope profiles of carbonate rocks at the Permian-Triassic boundary are rare, comparative studies on deep-water profiles were lacking for the major extinction event that occurred during this time. We present sections of different water depths in the Chibi area of southern China that we have selected for a comparative study. We analyzed carbon isotopes, calcium isotopes, as well as major and trace elements of carbonates from two sections (Chibi North and Chibi West) to obtain information on the volcanic activity, ocean acidification, as well as sea level rise and fall in the Chibi area during the mass extinction period. All carbon and calcium isotopes of carbonates from both sections are all negative after the mass extinction boundary. Carbonates from the Chibi North section have higher δ44/40Ca values and lower Sr/Ca ratios than the rocks from the Chibi West section. We propose that the negative bias of the calcium isotopes in the two sections result from diagenesis. Diagenesis transforms primary aragonite into calcite, showing the characteristics of high δ44/40Ca value and low Sr/Ca. By comparing our data with three published profiles of shallow-water carbonate rock, we recognize that calcium isotopes record gradients at different water depths. In the slope environment, the enhancement of pore fluid action near the coast caused an increase of the fluid buffer alteration, and we propose that a regression event occurred in the Chibi region during the Late Permian.

The Role of Orexin-1 Receptors Within the Hippocampal CA1 Area in the Extinction and Reinstatement of Methamphetamine-Seeking Behaviors.

Psychostimulant addiction is a chronic brain disorder with high relapse rates, requiring new therapeutic strategies. The orexin system is highly implicated in processing reward and addiction through connections with critical areas such as the hippocampus. This study investigated the role of orexin-1 receptors (OX1R) within the CA1 subregion of the hippocampus in the extinction and reinstatement of the methamphetamine-induced conditioned place preference. After cannulae implantation, recovery, and establishing the methamphetamine place preference, 98 male Wistar rats received different doses of bilateral intra-CA1 selective OX1R antagonist, SB334867 (1, 3, 10, and 30nmol/0.5μl DMSO per side) during the 10-day extinction period (daily) or after extinction phase, just on the reinstatement day (single dose) in separate experimental and control groups. The findings indicated that bilateral microinjection of SB334867 into the CA1 area during the extinction period could significantly reduce the extinction latency and maintenance of rewarding aspects of methamphetamine dose-dependently (3, 10, and 30nmol). In another set of experiments, a single dose of bilateral intra-CA1 SB334867 administration on the reinstatement phase prevented the methamphetamine-induced reinstatement of drug-seeking behaviors at the high doses (10, and 30nmol). The present study provided more evidence for the implication of hippocampal OX1R in the maintenance of rewarding and reinforcing properties of methamphetamine and its role in the relapse of methamphetamine-seeking behavior. Further investigations on the role of the orexin system, including the orexin-2 receptors in treating addiction, are needed to introduce its antagonists as effective therapeutic options for psychostimulant addiction.

Between Europeanisation and politicisation: wolf policy and politics in Germany

ABSTRACT The impact of Europeanisation on domestic policies is often associated with the alignment of European policies and discourses with national ones. The Habitats Directive mandating wolf protection entailed heated debates across the EU, suggesting diverging values and interests at various levels of policy-making. I present an analysis of wolf policy and politics in Germany, where wolves have returned after a long period of extinction. Tracing the dynamics of institutions involved in wolf management in 2000–2021, I identify key groups involved, their activities and positions as well as the impact of European rules and discourses. Unlike in some other Central in Eastern European countries, German wolf policy was strongly influenced by Europeanisation that helped to sustain the institutional path of wolf conservation, despite criticism from dominant land-use actors who politicised the issue to relax conservation rules. I suggest adding safeguarding of latent policies to the catalogue of outcomes of Europeanisation.

Individual differences in cocaine-induced conditioned place preference in male rats: Behavioral and transcriptomic evidence.

Background:Substance use disorder emerges in a small proportion of drug users and has the characteristics of a chronic relapsing pathology.Aims:Our study aimed to demonstrate and characterize the variability in the expression of the rewarding effects of cocaine in the conditioned place preference (CPP) paradigm.Methods:A cocaine-CPP paradigm in male Sprague–Dawley rats with an extinction period of 12 days and reinstatement was conducted. A statistical model was developed to distinguish rats expressing or not a cocaine-induced place preference.Results:Two groups of rats were identified: rats that did express rewarding effects (CPP expression (CPPE), score >102 s) and rats that did not (no CPP expression (nCPPE), score between −85 and 59 s). These two groups did not show significant differences in a battery of behavioral tests. To identify differentially expressed genes in the CPPE and nCPPE groups, a whole-transcriptome ribonucleic acid-sequencing analysis was performed in the nucleus accumbens (NAc) 24 h after the CPP test. Four immediate early genes (Fos, Egr2, Nr4a1, and Zbtb37) were differentially expressed in the NAc of CPPE rats after expression of CPP. Variability in cocaine-induced place preference persisted in the CPPE and nCPPE groups after the extinction and reinstatement phases. Transcriptomic differences observed after reinstatement were distinct from those observed immediately after expression of CPP.Conclusion:These new findings provide insights into the identification of mechanisms underlying interindividual variability in the response to cocaine’s rewarding effects.

Intra-Accumbal D1- But not D2-Like Dopamine Receptor Antagonism Reverses the Inhibitory Effects of Cannabidiol on Extinction and Reinstatement of Methamphetamine Seeking Behavior in Rats.

Introduction: Methamphetamine (METH) is an addictive psychostimulant that facilitates dopamine transmission to the nucleus accumbens (NAc), resulting in alterations in the mesocorticolimbic brain regions. Cannabidiol (CBD) is considered the second most abundant component of cannabis and is believed to decrease the METH effects. Reversing psychostimulant-induced abnormalities in the mesolimbic dopamine system is the main mechanism for this effect. Various other mechanisms have been proposed: increasing endocannabinoid system activity and modulating gamma-aminobutyric acid (GABA) and glutamate neurons in NAc. However, the exact CBD action mechanisms in reducing drug addiction and relapse vulnerability remain unclear. Methods and Results: The present study aimed to investigate the effects of intracerebroventricular (ICV) administrating 5, 10, and 50 μg/5 μL CBD solutions on the extinction period and reinstatement phase of a METH-induced conditioned place preference. This research also aimed to examine the NAc D1-like dopamine receptor (D1R) and D2-like dopamine receptor (D2R) roles in the effects of CBD on these phases, as mentioned earlier, using SCH23390 and sulpiride microinjections as an antagonist of D1R and D2R. The obtained results showed that microinjection of CBD (10 and 50 μg/5 μL, ICV) suppressed the METH-induced reinstatement and significantly decreased mean extinction latency in treated groups compared to both vehicles and/or untreated control groups. In addition, the results demonstrated that administrating intra-accumbal SCH23390 (1 and 4 μg/0.5 μL saline) reversed the inhibitory effects of CBD on extinction and reinstatement phases while different doses of sulpiride (0.25, 1, and 4 μg/0.5 μL; dimethyl sulfoxide 12%) could not alter the CBD effects. Conclusions: In summary, this study showed that CBD made shorter extinction latencies and suppressed the METH reinstatement, in part, by interacting with D1R but not D2R in the NAc.

새와 공룡의 연계성: 조류는 공룡으로부터 진화

Aves including chickens are currently one of the most representative vertebrates on the planet. More than 10,000 bird species are distributed among various regions around the world. Dinosaurs, which evolved from archosaurs, were once assumed to have gone extinct during the Cretaceous-Paleozoic extinction period. Since the mid-1990s, abundant dinosaur fossils have been found in China and various other parts of the world. Research articles on phylogenetic, evolutionary, and genomic studies of fossil taxa show that birds are living theropod dinosaurs. This review describes the link between birds and dinosaurs based on studies of their skeletal structures, feathers, respiratory organs, chromosomes, and metabolism. Birds are the only theropod dinosaurs that survived the mass extinction 66 million years ago. Dinosaurs did not go extinct and we are still living in the age of the dinosaurs.

Acute treatment with the glucagon-like peptide-1 receptor agonist, liraglutide, reduces cue- and drug-induced fentanyl seeking in rats

Opioid Use Disorder (OUD) is a chronic relapsing disorder that has severe negative impacts on the individual, the family, and the community at large. In 2021, opioids contributed to nearly 70% of all drug overdose deaths in the United States. This number of opioid related deaths coincides with a significant rise in the use of fentanyl, a synthetic opioid that is 150 times more potent than morphine. Furthermore, this overdose trend has spared no demographic and costs the nation an estimated $51.2 billion annually. Thus, it is imperative to better understand the underlying mechanisms of OUD in an effort to identify new treatment targets. Using animal models, studies have shown that rats readily self-administer heroin and increase seeking following exposure to cues for drug, the drug itself, or stress. We have shown that treatment with the glucagon-like peptide-1 receptor (GLP-1R) agonist, liraglutide, can reduce heroin taking and seeking behavior in rats. Therefore, using our rodent model, we established a fentanyl self-administration paradigm to test whether acute treatment with the GLP-1R agonist also can reduce fentanyl seeking in fentanyl experienced rats. The results showed that rats readily self-administered fentanyl (2.5 ug/kg) intravenously, with marked individual differences in drug taking behavior. As with other drugs of abuse tested, rats exhibited high seeking behavior when challenged with a drug-related cue or, after a period of extinction, the drug itself. Here, acute treatment with the GLP-1R agonist, liraglutide (0.3 mg/kg s.c.), was found to attenuate both cue-induced fentanyl seeking and drug-induced reinstatement of fentanyl seeking with the same efficacy as the currently approved partial opioid agonist, buprenorphine. Taken together, these data suggest that a known satiety signal, GLP-1, may serve as an effective non-opioid alternative for the treatment of OUD.

Hypocretin/orexin system in the nucleus accumbens as a promising player in the extinction and reinstatement of methamphetamine-induced CPP

One of the main obstacles in treating psychostimulant addiction is relapse even after long-term abstinence. The nucleus accumbens (NAc) is located in the basal forebrain, responsible for regulating several behaviors, specifically reward-related effect of psychostimulants. In the current study, an unbiased place conditioning paradigm was performed to inquire the role of the hypocretin/orexin system in the NAc in the extinction and reinstatement of methamphetamine (Meth)-induced conditioned place preference (CPP). Similar to previous investigations, rats were conditioned with Meth (1 mg/kg; sc) for five consecutive days to elicit CPP. The rats underwent Meth conditioning protocol received SB334867 or TCS OX2 29, an orexin receptor 1 (OXr1) antagonist or orexin receptor 2 (OXr2) antagonist (0, 3, 10, and 30 nmol/0.5 μL DMSO %12) in the NAc during the extinction period to elucidate the role of OXrs on the extinction of Meth-induced CPP. Meanwhile, extinguished rats received SB334867 or TCS OX2 29 (0, 1, 3, 10, and 30 nmol/0.5 μL DMSO %12) in the NAc prior to an effective priming dose of Meth to evaluate the impact of OXr antagonists on the reinstatement of Meth-induced CPP. The current data pointed out intra-NAc microinjection of SB334867 or TCS OX2 29 blocked both extinction and reinstatement of Meth-induced CPP. In addition, the OXr1 antagonist was more potent than the OXr2 antagonist to suppress both extinction and reinstatement phases of Meth-induced CPP. Based on the current data, the OX system in the NAc is extensively implicated in the reward properties of Meth; therefore, modulation of this system has therapeutic potential in treating psychostimulant use disorders.

Maternal sleep deprivation affects extinction and reinstatement of methamphetamine reward memory in male offspring: Role of the D1-like and D2-like dopamine receptors

Maternal sleep-deprivation (MSD) has been shown to induce stress, hyperactivity, and risk taking behavior in the offspring; howbeit, it is not yet clear whether it may also affect vulnerability to psychostimulant abuse in the offspring. We aimed to determine whether MSD affects extinction and reinstatement of methamphetamine (METH) reward memory in the offspring and also to evaluate the possible role of dopamine D1-like and D2-like receptors in these processes. Thirty-day-old male offspring born to control and sleep-deprived dams (during the third week of pregnancy) were trained to acquire METH-induced place preference (2 mg/kg., i.p.). METH reward memory was then reinstated following an 8-day period of extinction. The offspring received SCH 23390 (0.03 or 0.1 mg/kg, i.p.) or sulpiride (20 or 60 mg/kg, i.p.) as antagonists of dopamine D1-like and D2-like receptors, respectively, either immediately after each daily extinction session or prior to the reinstatement session. MSD postponed METH extinction and facilitated METH reinstatement in the offspring. SCH 23390 facilitated METH extinction and decreased reinstatement of the extinguished METH preference. Sulpiride in the offspring from sleep-deprived dams facilitated METH extinction, but it did not affect reinstatement of the extinguished METH reward memory. It seems that MSD may enhance vulnerability to METH abuse in the offspring. Furthermore, both dopamine D1-like and D2-like receptors may mediate METH extinction in the offspring born to the sleep-deprived dams; however, only the dopamine D1 receptor may play an important role in reinstating the extinguished METH reward memory in the offspring.

Estimating the Drivers of Diversification of Stoneflies Through Time and the Limits of Their Fossil Record

AbstractDeciphering the timing of lineage diversification and extinction has greatly benefited in the last decade from methodological developments in fossil-based analyses. If these advances are increasingly used to study the past dynamics of vertebrates, other taxa such as insects remain relatively neglected. Our understanding of how insect clades waxed and waned or of the impact of major paleoenvironmental changes during their periods of diversification and extinction (mass extinction) are rarely investigated. Here, we compile and analyze the fossil record of Plecoptera (1,742 vetted occurrences) to investigate their genus-level diversification and diversity dynamics using a Bayesian process-based model that incorporates temporal preservation biases. We found that the Permian-Triassic mass extinction has drastically impacted Plecoptera, while the Cretaceous Terrestrial Revolution corresponds with a turnover of plecopteran fauna. We also unveiled three major gaps in the plecopteran fossil record: the Carboniferous-Permian transition, the late Early Cretaceous, and the late Cenomanian to Bartonian, which will need to be further investigated. Based on the life history of extant Plecoptera, we investigate the correlations between their past dynamic and a series of biotic (Red Queen hypothesis) and abiotic (Court Jester hypothesis) factors. These analyses highlight the major role of continental fragmentation in the evolutionary history of stoneflies, which is in line with phylogeny-based biogeographic analyses showing how vicariance drove their diversification. Our study advocates analyzing the fossil record with caution, while attempting to unveil the diversification and extinction periods plus the likely triggers of these past dynamics of diversification.

Effect of Testosterone on the Extinction Period of Morphine-induced CPP in Male Rats

Background: Sex-related differences in the incidence, prevalence, symptoms, and side effects of drug use, especially narcotics, have been previously shown in animal models and human studies. Objectives: In the presents study, the effects of different doses of testosterone on morphine extinction period were investigated in a rat model. Methods: Forty mature male Wistar rats were randomly allocated to four categories (10 in each group), including control (received intramuscular injection of vehicle) and testosterone (received intramuscular injection of testosterone at 1, 2.5 and 5 mg/kg) during the extinction period. Conditioned place preference (CPP) test was done to assess the psychological phenomena of drug craving and relapse. The CPP score was calculated in four stages, including the baseline (preconditioning), expression (postconditioning), extinction, and reinstatement. Results: Our results demonstrated that testosterone (1, 2.5 and 5 mg/kg) significantly extended morphine extinction duration compared to the control group. Conclution: It has been shown that dopamine neurotransmission in mesocorticolimbic system is affected by testosterone through androgen receptors in adolescence and alteration in testosterone level could affect drug use vulnerability. It seems that normalization of testosterone levels reduces the symptoms of opioid withdrawal syndrome and have important clinical implication for clinicians to understand the effects of testosterone dysregulation on the extinction and withdrawal periods.

Slowing Time in the Museum in a Period of Rapid Extinction

Extinction of nonhuman species, as well as human-induced environmental change in general, is happening at a frighteningly fast pace. A recent global joint scientific assessment suggests that around a million animal and plant species are currently threatened with extinction because of human activity. In this article, we propose that museums have an opportunity to slow time for their visitors in a period of rapid extinction. First, we discuss the role of museums as galleries for active reflection and encounter with the loss inherent in extinction by changing the time scales in which people think and move. Then we introduce the articles in this themed issue on Exhibiting Extinction as all grappling with the tension between fast environmental loss and taking the necessary time to reckon with extinction. Time functions on another scale when extinction is involved, with the jumbling of past, present, and future. We argue that offering ways for people to think about and with extinction by slowing down time may be museums’ greatest contribution to addressing the real and present danger of extinction.

PM2.5 in Carlsbad Caverns National Park: Composition, sources, and visibility impacts

ABSTRACT Carlsbad Caverns National Park in southeastern New Mexico is adjacent to the Permian Basin, one of the most productive oil and gas regions in the country. The 2019 Carlsbad Caverns Air Quality Study (CarCavAQS) was designed to examine the influence of regional sources, including urban emissions, oil and gas development, wildfires, and soil dust on air quality in the park. Field measurements of aerosols, trace gases, and deposition were conducted from 25 July through 5 September 2019. Here, we focus on observations of fine particles and key trace gas precursors to understand the important contributing species and their sources and associated impacts on haze. Key gases measured included aerosol precursors, nitric acid and ammonia, and oil and gas tracer, methane. High-time resolution (6-min) PM2.5 mass ranged up to 31.8 µg m−3, with an average of 7.67 µg m−3. The main inorganic ion contributors were sulfate (avg 1.3 µg m−3), ammonium (0.30 µg m−3), calcium (Ca2+) (0.22 µg m−3), nitrate (0.16 µg m−3), and sodium (0.057 µg m−3). The WSOC concentration averaged 1.2 µg C m−3. Sharp spikes were observed in Ca2+, consistent with local dust generation and transport. Ion balance analysis and abundant nitric acid suggest PM2.5 nitrate often reflected reaction between nitric acid and sea salt, forming sodium nitrate, and between nitric acid and soil dust containing calcium carbonate, forming calcium nitrate. Sulfate and soil dust are the major contributors to modeled light extinction in the 24-hr average daily IMPROVE observations. Higher time resolution data revealed a maximum 1-hr extinction value of 90 Mm−1 (excluding coarse aerosol) and included periods of significant light extinction from BC as well as sulfate and soil dust. Residence time analysis indicated enrichment of sulfate, BC, and methane during periods of transport from the southeast, the direction of greatest abundance of oil and gas development. Implications: Rapid development of U.S. oil and gas resources raises concerns about potential impacts on air quality in National Parks. Measurements in Carlsbad Caverns National Park provide new insight into impacts of unconventional oil and gas development and other sources on visual air quality in the park. Major contributors to visibility impairment include sulfate, soil dust (often reacted with nitric acid), and black carbon. The worst periods of visibility and highest concentrations of many aerosol components were observed during transport from the southeast, a region of dense Permian Basin oil and gas development.