Regulation of Motor Function and Behavior by Atypical Chemokine Receptor 1

The final publication is available at Springer via http://dx.doi.org/10.1007/s10519-014-9665-7Atypical Chemokine Receptor 1 (ACKR1), previously known as the Duffy Antigen Receptor for Chemokines, stands out among chemokine receptors for its high selective expression on Purkinje cells of the cerebellum, consistent with the ability of ACKR1 ligands to activate Purkinje cells in vitro. Nevertheless, evidence for ACKR1 regulation of brain function in vivo has been lacking. Here we demonstrate that Ackr1−/− mice have markedly impaired balance and ataxia when placed on a rotating rod and increased tremor when injected with harmaline, a drug that induces whole-body tremor by activating Purkinje cells. Ackr1−/− mice also exhibited impaired exploratory behavior, increased anxiety-like behavior and frequent episodes of marked hypoactivity under low-stress conditions. The behavioral phenotype of Ackr1−/− mice was the opposite of the phenotype occurring in mice with cerebellar degeneration and the defects persisted when Ackr1 was deficient only on non-hematopoietic cells. We conclude that normal motor function and behavior depend in part on negative regulation of Purkinje cell activity by Ackr1

The effect of long-term repeated exposure to 3,4-methylenedioxymethamphetamine on cardiovascular and thermoregulatory changes

Rationale3,4-Methylenedioxymethamphetamine (MDMA, "ecstasy") disrupts thermoregulation in rats and can lead to life-threatening hyperthermia in humans. MDMA administration can also lead to long-term neurotoxicity in animals and possibly humans.ObjectivesThe purpose of the current study was to extend previous results on the acute effects of MDMA on behavioral thermoregulation to a repeated dosing regime, simulating regular weekend use of ecstasy, on measures of thermoregulation and heart rate (HR).Materials and methodsSprague-Dawley rats with telemetry implants were administered 40 micromol/kg MDMA on three consecutive days each week for 1 or 6 weeks before being confined to an elevated ambient temperature (TA) (HOT; 30+/-1 degrees C) or an area at room temperature (ROOM; 21.5+/-1.5 degrees C) for 30 min. After the final drug administration, rats were placed in a thermal gradient for 4 h to allow behavioral thermoregulation.ResultsHOT rats showed higher core temperature (TC), HR, and locomotor activity than ROOM rats during confinement to a set TA (PConclusionLong-term treatment with MDMA resulted in apparent tolerance to the effects of the drug on HR, dysregulation of TC in thermal gradient, and depletion of cortical DOPAC and 5-HIAA.Emily Joy Jaehne, Abdallah Salem, Rodney James Irvin

Pharmacological and behavioral determinants of cocaine, methamphetamine, 3,4-methylenedioxymethamphetamine, and para -methoxyamphetamine-induced hyperthermia

The original publication is available at www.springerlink.comRationale: Cocaine, methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA, ecstasy), and para-methoxyamphetamine (PMA) disrupt normal thermoregulation in humans, with PMA being associated with more severe cases of hyperthermia. Harm minimization advice on how to prevent overheating depends on appropriate thermoregulatory behavior by drug users. Objectives: The purpose of the current study was to establish dose–response relationships for the effects of a number of commonly used illicit stimulants and investigate the behavioral response to increased core temperature. Materials and methods Sprague-Dawley rats with telemetry implants were administered either saline or 4, 12, 26, 40 or 80 μmol/kg of cocaine, methamphetamine, MDMA, or PMA and confined to an ambient temperature of 30°C for 30 min, before being able to choose their preferred temperature on a thermally graded runway (11-41°C). Results: The increased core temperature caused by administration of cocaine, methamphetamine, and MDMA treatment led to the animals seeking the cool end of the runway to correct their core temperature, although this did not occur in PMA-treated rats. The order of potency for increasing core temperature was methamphetamine >PMA = MDMA> cocaine. This differed to the slopes of the dose–response curves where MDMA and PMA showed the steepest slope for the doses used followed by methamphetamine then cocaine. Conclusions: These results suggest that behavioral aspects of thermoregulation are important in assessing the potential of individual drugs to cause harmful increases in core temperature.Emily Joy Jaehne, Abdallah Salem and Rodney James Irvin

Synapse development organized by neuronal activity-regulated immediate-early genes

Classical studies have shown that neuronal immediate-early genes (IEGs) play important roles in synaptic processes critical for key brain functions. IEGs are transiently activated and rapidly upregulated in discrete neurons in response to a wide variety of cellular stimuli, and they are uniquely involved in various aspects of synapse development. In this review, we summarize recent studies of a subset of neuronal IEGs in regulating synapse formation, transmission, and plasticity. We also discuss how the dysregulation of neuronal IEGs is associated with the onset of various brain disorders and pinpoint key outstanding questions that should be addressed in this field. © 2018 The Author(s).1