Repeated cocaine treatments induce distinct locomotor effects in Crayfish

Evaluation of freshwater heavy metals accumulation effect on oxidative stress, Metallothionein biosynthesis and histopathology of Procambarus clarkii (Girard,1985) collected from three locations in the Delta region, Egypt

BACKGROUND

In this study, the effect of heavy metals accumulation influence was evaluated on adult crayfish Procambarus clarkii (Decapoda, Astacidea) collected from three different Governmental locations (Kafr El-Shaikh, El-Menofya, and El-Gharbiya) of the Egyptian Delta. The activity of super oxidase dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) of gills, hepatopancreas, and muscle tissue were measured. SDS Polyacrylamide gel electrophoresis (SDS-PAGE) and West blotting technique were performed to detect MT Protein expression.

RESULTS

The results revealed that Kafr El-Shaikh reflected the highest Superoxide dismutase (SOD), Catalase, and Glutathione S-transferase (GST) activity levels (97.2 u/100 mg, 28.5 u/100 mg, and 8.3 nmol mg (-1) protein min (-1) respectively. Superior protein polymorphism % (30%) remarked collected Freshwater crayfish P. clarkii from Kafr El-Shaikh location. Varied protein polymorphism % was shown between collected crayfish from El-Menofya, and El-Gharbiya locations (5.5 and 6.2 respectively) Increasing Metallothioneins intensity (15.4%) for collected Freshwater crayfish Procambarus clarkii from Kafr El-Shaikh Location.

CONCLUSION

Heavy metal stress influences antioxidant status and also induces increasing Metallothioneins intensity, especially samples that were collected from the Kafr El-Shaikh area.

Psychoactive compounds at environmental concentration alter burrowing behavior in the freshwater crayfish

Pharmaceutically active compounds (PhAC) have been increasingly detected in freshwater and marine waterbodies worldwide and are recognized as major emerging micropollutant threat to the aquatic environment. Despite their low concentrations in the environment, there is evidence of effects on non-target aquatic organisms in natural habitats. To assess the potential effects of PhACs on its burrowing behavior, we exposed the red swamp crayfish Procambarus clarkii to methamphetamine or tramadol at the environmentally relevant concentration of 1 μg/L. Methamphetamine-exposed females constructed burrows of lower depth and volume relative to individual weight than did controls. Tramadol-exposed females consistently exhibited a tendency for smaller burrows, but this difference was not significant. Exposed males showed a non-significant tendency to excavate larger burrows compared with the control. Control and tramadol-treated females maintained the natural tendency of constructing relatively deeper and/or larger-volume burrows compared with males. This sex-related pattern was not detected in the methamphetamine group. The rate of human therapeutic PhAC usage is relatively stable year-round, and impacts on crayfish burrowing can be particularly damaging during periods of drought, when the dilution of waste waters is reduced, and burrowing becomes a critical survival strategy. Our results suggest that an increasingly broad range of environmental impacts of PhACs on non-target organisms can be expected in natural ecosystems.

Cardiac and Locomotor Responses to Acute Stress in Signal Crayfish Pacifastacus leniusculus Exposed to Methamphetamine at an Environmentally Relevant Concentration

Methamphetamine (METH), a central nervous system stimulant used as a recreational drug, is frequently found in surface waters at potentially harmful concentrations. To determine effects of long-term exposure to environmentally relevant levels on nontarget organisms, we analysed cardiac and locomotor responses of signal crayfish Pacifastacus leniusculus to acute stress during a 21-day exposure to METH at 1 μg L^-1 followed by 14 days depuration. Heart rate and locomotion were recorded over a period of 30 min before and 30 min after exposure to haemolymph of an injured conspecific four times during METH exposure and four times during the depuration phase. Methamphetamine-exposed crayfish showed a weaker cardiac response to stress than was observed in controls during both exposure and depuration phases. Similarly, methamphetamine-exposed crayfish, during METH exposure, showed lower locomotor reaction poststressor application in contrast to controls. Results indicate biological alterations in crayfish exposed to METH at low concentration level, potentially resulting in a shift in interactions among organisms in natural environment.

Crayfish as Bioindicators for Monitoring ClO2: A Case Study from a Brewery Water Treatment Facility

This study focuses on the use of crayfish as bioindicators in the water treatment process during operating conditions. The crayfish physiological responses to water disinfected with chlorine dioxide (ClO2) was evaluated. Monitoring was conducted at the private commercial enterprise Protivín Brewery in Czech Republic under standard operating conditions. This brewery has a water treatment facility, where ClO2 is used for water purification. A total of 25 adult signal crayfish (Pacifastacus leniusculus) were kept in separate flow-through aquaria receiving the purified water with ClO2 concentrations ranging from 0.01 to 0.29 mg L−1. Diurnal rhythms of 32% of crayfish was disturbed even at lower concentrations of ClO2 (0.01–0.2 mg L−1), while higher concentrations (>0.2 mg L−1) affected all animals. A random decline and rise of heart rate was detected. In addition, the frequent occurrence of higher levels of ClO2 significantly increased mortality. On average, mortality of crayfish occurred three to four weeks after stocking into the experimental system. Crayfish mortality is estimated to occur at concentrations exceeding 0.2 mg L−1 of ClO2. Our results suggest that long-term exposure to ClO2 adversely affects crayfish physiology. In addition, the results of this study could contribute to the use of crayfish as bioindicators in long-term water quality monitoring under industrial conditions.

Biochemical and behavioral effects induced by cocaine exposure to Daphnia magna

Illicit drugs and their metabolites have been identified as emerging aquatic pollutants. Cocaine (COC) is one of the most used illicit drug worldwide. After human consumption, COC enters the aquatic ecosystems, where it is commonly detected in ng L^-1 concentration range. Although a number of studies have shown that the exposure to environmental concentrations of COC can induce diverse biochemical, molecular and histological effects on aquatic organisms, the information of COC-induced behavioral alterations is scant. Thus, the present study aimed at exploring both biochemical and behavioral effects induced by the exposure to two environmental concentrations (50 ng L^-1 and 500 ng L^-1) of COC on the freshwater cladoceran Daphnia magna. Specimens were exposed to selected COC concentrations for 21 days and the effects on the oxidative status, including the amount of reactive oxygen species and the activity of antioxidant (SOD, CAT and GPx) and detoxifying (GST) enzymes, and swimming activity were investigated after 7, 14 and 21 days of treatment, while effects on reproductive success was assessed after 21-days only.. Exposure to COC induced an overproduction of reactive oxygen species and a modulation of the activity of defense enzymes. Moreover, COC affected the swimming behavior and altered the reproductive success of treated specimens. Our results highlighted that environmental concentrations of COC can cause adverse effects at different levels of the biological hierarchy in a zooplanktonic species, confirming the potential threat due to this illicit drug for the aquatic community.

The crayfish model (Orconectes rusticus), epigenetics and drug addiction research

Fundamental signs of epigenetic effects are variations in the expression of genes or phenotypic traits among isogenic mates. Therefore, genetically identical animals are in high demand for epigenetic research. There are many genetically identical animals, including natural parthenogens and inbred laboratory lineages or clones. However, most parthenogenetic animal taxa are very small in combined epigenetic and drug addiction research. Orconectes rusticus has a unique phylogenetic position, with 2-3 years of life span, which undergoes metamorphosis that creates developmental stages with distinctly different morphologies, unique lifestyles, and broad behavioral traits, even among isogenic mates reared in the same environment offer novel inroads for epigenetics studies. Moreover, the establishment of crayfish as a novel system for drug addiction with evidence of an automated, operant self-administration and conditioned-reward, withdrawal, reinstatement of the conditioned drug-induced reward sets the stage to investigate epigenetic mechanisms of drug addiction. We discuss behavioral, pharmacological and molecular findings from laboratory studies that document a broad spectrum of molecular and, behavioral evidence including potential hypotheses that can be tested with the crayfish model for epigenetic study in drug addiction research.

Crayfish Self-Administer Amphetamine in a Spatially Contingent Task

Natural reward is an essential element of any organism’s ability to adapt to environmental variation. Its underlying circuits and mechanisms guide the learning process as they help associate an event, or cue, with the perception of an outcome’s value. More generally, natural reward serves as the fundamental generator of all motivated behavior. Addictive plant alkaloids are able to activate this circuitry in taxa ranging from planaria to humans. With modularly organized nervous systems and confirmed vulnerabilities to human drugs of abuse, crayfish have recently emerged as a compelling model for the study of the addiction cycle, including psychostimulant effects, sensitization, withdrawal, reinstatement, and drug reward in conditioned place preference paradigms. Here we extend this work with the demonstration of a spatially contingent, operant drug self-administration paradigm for amphetamine. When the animal enters a quadrant of the arena with a particular textured substrate, a computer-based control system delivers amphetamine through an indwelling fine-bore cannula. Resulting reward strength, dose-response, and the time course of operant conditioning were assessed. Individuals experiencing the drug contingent on their behavior, displayed enhanced rates of operant responses compared to that of their yoked (non-contingent) counterparts. Application of amphetamine near the supra-esophageal ganglion elicited stronger and more robust increases in operant responding than did systemic infusions. This work demonstrates automated implementation of a spatially contingent self-administration paradigm in crayfish, which provides a powerful tool to explore comparative perspectives in drug-sensitive reward, the mechanisms of learning underlying the addictive cycle, and phylogenetically conserved vulnerabilities to psychostimulant compounds.

Operant avoidance learning in crayfish, Orconectes rusticus: Computational ethology and the development of an automated learning paradigm

Research in crustaceans offers a valuable perspective for studying the neural implementation of conserved behavioral phenomena, including motivation, escape, aggression, and drug-sensitive reward. The present work adds to this literature by demonstrating that crayfish successfully learn to respond to spatially contingent cues. An integrated video-tracking system automatically delivered a mild electric shock when a test animal entered or remained on a substrate paired with punishment. Following a few instances of shock delivery, crayfish quickly learned to avoid these areas. Comparable changes in substrate preference were not exhibited by yoked controls, but locomotion differed significantly from both pre-conditioning levels and from those of their masters receiving shock in a contingent fashion. The results of this work provide valuable insights into the principles governing avoidance learning in an invertebrate system and provide a behavioral template for exploring the neural changes during associative learning. Serving as a case study, this project introduces a new computer framework for the automated control of learning paradigms. Based on routines contained within the JavaGrinders library (free download at iEthology.com), it integrates real-time video tracking with robotic interfaces, and provides a suitable framework for implementing automated learning paradigms.

The Sensitivity of the Crayfish Reward System to Mammalian Drugs of Abuse

The idea that addiction occurs when the brain is not able to differentiate whether specific reward circuits were triggered by adaptive natural rewards or falsely activated by addictive drugs exist in several models of drug addiction. The suitability of crayfish (Orconectes rusticus) for drug addiction research arises from developmental variation of growth, life span, reproduction, behavior and some quantitative traits, especially among isogenic mates reared in the same environment. This broad spectrum of traits makes it easier to analyze the effect of mammalian drugs of abuse in shaping behavioral phenotype. Moreover, the broad behavioral repertoire allows the investigation of self-reinforcing circuitries involving appetitive and exploratory motor behavior, while the step-wise alteration of the phenotype by metamorphosis allows accurate longitudinal analysis of different behavioral states. This paper reviews a series of recent experimental findings that evidence the suitability of crayfish as an invertebrate model system for the study of drug addiction. Results from these studies reveal that unconditioned exposure to mammalian drugs of abuse produces a variety of stereotyped behaviors. Moreover, if presented in the context of novelty, drugs directly stimulate exploration and appetitive motor patterns along with molecular processes for drug conditioned reward. Findings from these studies indicate the existence of drug sensitive circuitry in crayfish that facilitates exploratory behavior and appetitive motor patterns via increased incentive salience of environmental stimuli or by increasing exploratory motor patterns. This work demonstrates the potential of crayfish as a model system for research into the neural mechanisms of addiction, by contributing an evolutionary, comparative context to our understanding of natural reward as an important life-sustaining process.

Cocaine tolerance in honey bees

Increasingly invertebrates are being used to investigate the molecular and cellular effects of drugs of abuse to explore basic mechanisms of addiction. However, in mammals the principle factors contributing to addiction are long-term adaptive responses to repeated drug use. Here we examined whether adaptive responses to cocaine are also seen in invertebrates using the honey bee model system. Repeated topical treatment with a low dose of cocaine rendered bees resistant to the deleterious motor effects of a higher cocaine dose, indicating the development of physiological tolerance to cocaine in bees. Cocaine inhibits biogenic amine reuptake transporters, but neither acute nor repeated cocaine treatments caused measurable changes in levels of biogenic amines measured in whole bee brains. Our data show clear short and long-term behavioural responses of bees to cocaine administration, but caution that, despite the small size of the bee brain, measures of biogenic amines conducted at the whole-brain level may not reveal neurochemical effects of the drug.