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Arackal, J. S.

Publications and source records attributed to Arackal, J. S..

2 recordsLinked to original sources

Punishment Risk Task: Monitoring anxiogenic states during goal directed actions in mice

Summary/AbstractCanonical preclinical studies of anxiety-related behavioral states use exploration of novel spaces to test approach-avoidance conflicts such as the open field test, elevated plus maze, and light-dark box. However, these assays cannot evaluate complicated behaviors in which competing states of motivation result in anxiogenic behaviors. Furthermore, these assays can only test the approach-avoidance conflict once due to a reliance on spatial novelty. Here we demonstrate the punishment risk task (PRT) in male and female, group- and singly-housed mice, a model initially described in singly-housed male rats by Park and Moghaddam (2017). The task tests how probabilistic punishment affects reward-seeking behavior. In particular, it measures the delay to pursue a reward (sweetened food pellet) while the likelihood of punishment (foot shock) actively impinges reward-associated actions. Here, we found that mice show increased latency to respond to food reward cues in trials in which the probability of punishment is highest. Further, anxiolytic treatment with diazepam or propranolol block any increase in response latency, indicating the models potential to for study of anxiogenesis in mice. Elucidating how these competitive behavioral states are integral to adaptive behavior and change over time and experience to coordinate anxiogenesis should greatly benefit anxiety disorder research. Specifically, implementing this assay in mice will enable cell-type selective interrogation of these processes and further our understanding of the neural basis of anxiogenesis.

neuroscience↗

Peripheral kappa opioid receptor activation drives cold hypersensitivity in mice

Noxious cold sensation is commonly associated with peripheral neuropathies, however, there has been limited progress in understanding the mechanism of cold pain. Here we identify a role for kappa opioid receptors (KOR) in driving noxious cold hypersensitivity. First, we show that systemic activation of KOR by the agonist U50,488 (U50), increases the latency to jump and the number of jumps on a cold plate at 3{degrees}C, and that the KOR antagonist NorBNI attenuates U50-induced noxious cold hypersensitivity. However, the central administration of NorBNI does not block U50-induced noxious cold hypersensitivity, suggesting that peripheral KOR may modulate this effect. To directly test this, we use the peripherally-restricted KOR agonist, ff(nle)r-NH2 and also show selective activation of peripheral KOR causes noxious cold hypersensitivity. To begin to understand how peripheral KOR drive noxious cold hypersensitivity we investigated whether KOR interact with transient receptor potential ankyrin 1(TRPA1) channels, known to facilitate the perception of noxious cold, in dorsal root ganglion (DRG). Using fluorescent in situ hybridization, we show that KOR mRNA colocalizes with the transcripts for the cold-activated TRPA1 channels in DRG. We also show a potentiation in intracellular calcium release in DRG neurons during the simultaneous application of the TRPA1 agonist, mustard oil (MO), and a KOR agonist, U50, when compared to MO alone. Together our data suggest that peripheral KOR may induce noxious cold hypersensitivity through modulation of TRPA1 channels.

neuroscience↗