Browsing by Author "Pang, Daniel"

Now showing 1 - 4 of 4
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    Assessing Rodent Euthanasia Methods through Evaluation of Physiological Parameters
    (2014-01-30) Chisholm, Jessica; Pang, Daniel; Whelan, Patrick
    Two million rodents are euthanized in Canada annually; the majority of these animals will be euthanized with carbon dioxide gas. Avoidance-approach studies have indicated that its use is aversive for rodents. Other studies have linked CO2 nasal nociceptor activation (painful in humans) to bradycardia. This study assessed the following euthanasia methods through evaluation of physiological parameters (electroencephalography, electrocardiography, electromyography): carbon dioxide, isoflurane, carbon dioxide/oxygen and sodium pentobarbital. Loss of consciousness was assessed by testing the righting reflex. Thirty-two adult female Sprague-Dawley rats were instrumented with telemetric transmitters and euthanized seven days post-instrumentation. Carbon dioxide caused bradycardia in rats prior to loss of consciousness, the severity of bradycardia was lessened by the addition of supplemental oxygen. Carbon dioxide was the fastest euthanasia technique followed by isoflurane, carbon dioxide/oxygen and sodium pentobarbital. Neither recumbency nor muscle quiescence were reliable indicators of loss of consciousness. Overall isoflurane is the preferred method of euthanasia.
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    Consistency in Applying the Loss of Righting Reflex to Assess Unconsciousness during Induction of General Anesthesia in Rats and Mice: A Systematic Review Protocol
    (2022-06-29) Merenick, Dexter; Jessel, Anisha; Ganshorn, Heather; Pang, Daniel
    This systematic review protocol will evaluate the following question: How is the loss of righting reflex performed across studies to assess unconsciousness during induction of general anesthesia in rats and mice? The overall aim of this paper is to critically assess and evaluate the current published knowledge surrounding the LORR methodology and how it is performed.
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    The Evaluation of the Rat Grimace Scale and Ultrasonic Vocalisations as Novel Pain Assessment Tools in Laboratory Rats
    (2014-11-14) De Rantere, Debbie; Pang, Daniel
    Measuring pain in non-human mammals such as rodents is challenging. Recently, spontaneous behaviours including facial expression and ultrasonic vocalisation have been proposed as novel, alternative measures of pain. The goal of this research was to evaluate the applicability of ultrasonic vocalisations, and the Rat Grimace Scale (a recently developed facial expression pain scale) during gas exposure (for euthanasia purposes) and in models of inflammatory and incisional pain. First, I found that ultrasonic vocalisations were emitted during carbon dioxide, but not during isoflurane exposure. Secondly, the Rat Grimace Scale was able to detect inflammatory and incisional pain in rats. Additionally, the pain score obtained using the Rat Grimace Scale corresponded with the findings of a conventional nociceptive test using von Frey filaments. My work contributes to the further understanding of ultrasonic communicative behaviour and facial expression of rats experiencing pain and the application of grimace scales in in-vivo biomedical research.
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    The Role of Microglial P2X7 Receptor Phosphorylation in Neuropathic Pain
    (2016) Pilapil, Alexandra; Trang, Tuan; Zamponi, Gerald; Pang, Daniel; Gilch, Sabine
    Neuropathic pain is a debilitating chronic pain condition that can arise because of injury to a peripheral nerve. The lack of effective therapies for neuropathic pain demands a better understanding of the underlying mechanisms. Converging evidence suggests that neuropathic pain is caused by aberrant cellular and molecular changes within the central nervous system. Microglia and P2X7 receptors (P2X7Rs) are spinal targets implicated in neuropathic pain, but the core mechanisms that modulate microglial P2X7R activity remain obscure. We identified Y382-384 within the P2X7R C-terminal domain as a putative phosphorylation site that underlies nerve injury-induced mechanical allodynia in a sex-dependent mechanism. Thus, site-specific tyrosine phosphorylation of P2X7R in microglia is a novel spinal determinant involved in neuropathic pain for male animals. The findings of this study provide evidence for microglial-mediated sex differences in neuropathic pain, which further reinforces the importance of including male and female subjects in preclinical pain research.