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result(s) for
"Rabil, Maximilian J"
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Male DAT Val559 Mice Exhibit Compulsive Behavior under Devalued Reward Conditions Accompanied by Cellular and Pharmacological Changes
2022
Identified across multiple psychiatric disorders, the dopamine (DA) transporter (DAT) Ala559Val substitution triggers non-vesicular, anomalous DA efflux (ADE), perturbing DA neurotransmission and behavior. We have shown that DAT Val559 mice display a waiting impulsivity and changes in cognitive performance associated with enhanced reward motivation. Here, utilizing a within-subject, lever-pressing paradigm designed to bias the formation of goal-directed or habitual behavior, we demonstrate that DAT Val559 mice modulate their nose poke behavior appropriately to match context, but demonstrate a perseverative checking behavior. Although DAT Val559 mice display no issues with the cognitive flexibility required to acquire and re-learn a visual pairwise discrimination task, devaluation of reward evoked habitual reward seeking in DAT Val559 mutants in operant tasks regardless of reinforcement schedule. The direct DA agonist apomorphine also elicits locomotor stereotypies in DAT Val559, but not WT mice. Our observation that dendritic spine density is increased in the dorsal medial striatum (DMS) of DAT Val559 mice speaks to an imbalance in striatal circuitry that might underlie the propensity of DAT Val559 mutants to exhibit compulsive behaviors when reward is devalued. Thus, DAT Val559 mice represent a model for dissection of how altered DA signaling perturbs circuits that normally balance habitual and goal-directed behaviors.
Journal Article
Behaviorally penetrant, anomalous dopamine efflux exposes sex and circuit dependent regulation of dopamine transporters
by
Spiess, Keeley
,
Stewart, Adele
,
Gowrishankar, Raajaram
in
Attention deficit hyperactivity disorder
,
Autism
,
Caudate-putamen
2022
Virtually all neuropsychiatric disorders display sex differences in prevalence, age of onset, and/or clinical symptomology. Although altered dopamine (DA) signaling is a feature of many of these disorders, sex-dependent mechanisms uniquely responsive to DA that drive sex-dependent behaviors remain unelucidated. Previously, we established that anomalous DA efflux (ADE) is a prominent feature of the DA transporter (DAT) variant Val559, a coding substitution identified in two male-biased disorders: attention-deficit/hyperactivity disorder and autism spectrum disorder. In vivo, Val559 ADE induces activation of nigrostriatal D2-type DA autoreceptors (D2ARs) that magnifies inappropriate, nonvesicular DA release by elevating phosphorylation and surface trafficking of ADE-prone DAT proteins. Here we demonstrate that DAT Val559 mice exhibit sex-dependent alterations in psychostimulant responses, social behavior, and cognitive performance. In a search for underlying mechanisms, we discovered that the ability of ADE to elicit D2AR regulation of DAT is both sex and circuit-dependent, with dorsal striatum D2AR/DAT coupling evident only in males, whereas D2AR/DAT coupling in the ventral striatum is exclusive to females. Moreover, systemic administration of the D2R antagonist sulpiride, which precludes ADE-driven DAT trafficking, can normalize DAT Val559 behavioral changes unique to each sex and without effects on the opposite sex or wildtype mice. Our studies support the sex- and circuit dependent capacity of D2ARs to regulate DAT as a critical determinant of the sex-biased effects of perturbed DA signaling in neurobehavioral disorders. Moreover, our work provides a cogent example of how a shared biological insult drives alternative physiological and behavioral trajectories as opposed to resilience.
Journal Article
Serotonin transporter inhibition and 5-HT2C receptor activation drive loss of cocaine-induced locomotor activation in DAT Val559 mice
by
Peart, Rodeania
,
Stewart, Adele
,
Gowrishankar, Raajaram
in
Affinity
,
Amphetamines
,
Attention deficit hyperactivity disorder
2019
Dopamine (DA) signaling dysfunction is believed to contribute to multiple neuropsychiatric disorders including attention-deficit/hyperactivity disorder (ADHD). The rare DA transporter (DAT) coding substitution Ala559Val found in subjects with ADHD, bipolar disorder and autism, promotes anomalous DA efflux in vitro and, in DAT Val559 mice, leads to increased reactivity to imminent handling, waiting impulsivity, and enhanced motivation for reward. Here, we report that, in contrast to amphetamine and methylphenidate, which induce significant locomotor activation, cocaine administration to these mice elicits no locomotor effects, despite retention of conditioned place preference (CPP). Additionally, cocaine fails to elevate extracellular DA. Given that amphetamine and methylphenidate, unlike cocaine, lack high-affinity interactions with the serotonin (5-HT) transporter (SERT), we hypothesized that the lack of cocaine-induced hyperlocomotion in DAT Val559 mice arises from SERT blockade and augmented 5-HT signaling relative to cocaine actions on wildtype animals. Consistent with this idea, the SERT blocker fluoxetine abolished methylphenidate-induced locomotor activity in DAT Val559 mice, mimicking the effects seen with cocaine. Additionally, a cocaine analog (RTI-113) with greater selectivity for DAT over SERT retains locomotor activation in DAT Val559 mice. Furthermore, genetic elimination of high-affinity cocaine interactions at SERT in DAT Val559 mice, or specific inhibition of 5-HT2C receptors in these animals, restored cocaine-induced locomotion, but did not restore cocaine-induced elevations of extracellular DA. Our findings reveal a significant serotonergic plasticity arising in the DAT Val559 model that involves enhanced 5-HT2C signaling, acting independently of striatal DA release, capable of suppressing the activity of cocaine-sensitive motor circuits.
Journal Article
Risk Factors and Contemporary Management Options for Pain and Discomfort Experienced During a Prostate Biopsy
by
Sprenkle, Preston C.
,
Choksi, Ankur U.
,
Leapman, Michael S.
in
Medicine
,
Medicine & Public Health
,
Nephrology
2024
Purpose of Review
Prostate fusion biopsy, an innovative imaging modality for diagnosing prostate cancer, presents certain challenges for patients including discomfort and emotional distress, leading to nonadherence to treatment and follow-ups. To inform clinicians and offer pain relief alternatives to patients, this review delves into the risk factors for increased pain and modern management options to alleviate pain during prostate biopsy.
Recent Findings
Individual responses to pain vary, and the overall experience of pain during a prostate biopsy has been contributed to numerous factors such as patient age, prostate volume, previous biopsy experience, and more. As a result, several strategies aim to mitigate pain during in-office procedures. Notably, techniques including pharmacological analgesics, hand holding, heating pads, entertainment/virtual reality, and distraction have shown significant efficacy.
Summary
Existing studies explore risk factors influencing pain intensity during prostate biopsy and effective pain management strategies. This review consolidates available information to guide clinicians in enhancing patient comfort and thus, encourage surveillance adherence.
Journal Article
Discrepancies in volume: impact of Artemis segmented magnetic resonance imaging, ultrasound, and ExactVu measurements on prostate specific antigen density and National Comprehensive Cancer Network risk stratification
2025
The combination of magnetic resonance imaging (MRI) and ultrasound (US) allows for better lesion targeting and diagnostic probability compared to random prostate biopsies. The Artemis Fusion Biopsy system and ExactVu micro-US technology capitalize on this advantage and provide higher-resolution imaging of the prostate during biopsy. Their accuracy in measuring prostate volume and resulting implications on prostate specific antigen (PSA) density and risk stratification, however, has not been evaluated. We hypothesized that PSA densities as measured by these modalities will demonstrate clinically insignificant differences compared to standard measurement.
We retrospectively reviewed all prostate fusion biopsy cases performed at our health system with Artemis or ExactVu systems from April 2021 to July 2023 and compared the PSA density calculated from the volume obtained with these systems to standard measurement with ellipsoid calculation from MRI. Change in National Comprehensive Cancer Network (NCCN) prostate cancer risk stratification was analyzed for each system.
Artemis MRI segmentation (0.179 ng/ml, p = 0.04) and US (0.181 ng/ml, p = 0.067) underestimated and ExactVu micro-US (0.247 ng/ml, p <0.001) overestimated PSA density. Risk stratification changed in 1.2% of Artemis MRI segmentation cases, 1.6% of Artemis US cases, and 1.2% of ExactVu micro-US cases.
Despite differences in PSA density, choice of fusion biopsy system has minimal clinical impact on risk stratification and any of these studied systems may be used without fear of misrepresenting a patient's disease state.
Journal Article
DAT Val559 Mice Exhibit Compulsive Behavior Under Devalued Reward Conditions Accompanied by Cellular and Pharmacological Changes
2022
Identified across multiple psychiatric disorders, the dopamine (DA) transporter (DAT) Ala559Val substitution triggers non-vesicular, anomalous DA efflux (ADE), perturbing DA neurotransmission and behavior. We have shown that DAT Val559 mice display a waiting impulsivity and changes in cognitive performance associated with enhanced reward motivation. Here, utilizing a within-subject, lever-pressing paradigm designed to bias the formation of goal-directed or habitual behavior, we demonstrate that DAT Val559 mice modulate their nose-poke behavior appropriately to match context, but demonstrate a perseverative checking behavior. Although DAT Val559 mice display no issues with the cognitive flexibility required to acquire and re-learn a visual pairwise discrimination task, devaluation of reward evoked habitual reward seeking in DAT Val559 mutants in operant tasks regardless of reinforcement schedule. The direct DA agonist apomorphine also elicits locomotor stereotypies in DAT Val559, but not WT mice. Our observation that dendritic spine density is increased in the dorsal medial striatum (DMS) of DAT Val559 mice speaks to an imbalance in striatal circuitry that might underlie the propensity of DAT Val559 mutants to exhibit compulsive behaviors when reward is devalued. Thus, DAT Val559 mice represent a model for dissection of how altered DA signaling perturbs circuits that normally balance habitual and goal-directed behaviors.
Sex and Circuit Specific Dopamine Transporter Regulation Underlies Unique Behavioral Trajectories of Functional SLC6A3 Coding Variation
2021
Virtually all neuropsychiatric disorders display sex differences in prevalence, age of onset, and/or clinical symptomology. In sex-biased disorders, one sex is often suggested to harbor protective mechanisms, rendering them resilient to genetic and/or environmental risk factors. Here, we demonstrate sex-biased molecular, pharmacological and behavioral effects induced by the dopamine (DA) transporter (DAT) coding variant Ala559Val, previously identified in subjects diagnosed with the male-biased disorders attention-deficit/hyperactivity disorder and autism spectrum spectrum disorder. In DAT Val559 mice, we identified sex differences in response to psychostimulants, social behavior, and cognitive traits. We reveal a sex by circuit dissociation in D2-type autoreceptor (D2AR) regulation of DAT wherein D2AR-dependent DAT phosphorylation and trafficking, detectable in the male dorsal striatum, does not occur in females but rather is a property of the ventral striatum, predicting sex-specific changes in behavior. Consequently, we found that a subset of altered behaviors can be normalized using the D2R antagonist sulpiride in DAT Val559 mice. Our studies provide a cogent example of how sex shapes the behavioral trajectory of DA signaling perturbations and identify the sex-dependent, locality-selective capacity for D2AR regulation of DAT as an unrecognized determinant of this trajectory. Rather than identifying one sex as resilient, we find that sex can drive alterative behavioral patterns from shared signaling perturbations that may result in females being underreported. Our work underscores the utility of model systems to study the functional intrusions of rare genetic variation to gain insights into pathways underlying normal and perturbed trait domains associated with common neuropsychiatric conditions.