North American Pain School Conference

Posted on 02-12-2022 —

The application period for the North American Pain School (NAPS) 2023 is open!

The deadline to submit an application is January 27, 2023.

Improving public knowledge of pain mitigation strategies for adult vaccine injections

Posted on 10-12-2021 — Adult routine vaccination rates consistently fail to meet national targets in most countries. While factors affecting vaccine hesitancy are complex, concerns about pain and needle fears contribute to reduced vaccine uptake. Despite approximately one in four adults being afraid of needles, there is limited research on pain mitigation in adults receiving vaccinations. UTCSP member Dr. Anna Taddio and collaborators provided an educational pamphlet to adults receiving vaccine injections that outlines evidence-based pain mitigation strategies in order to assess its impact on knowledge, attitudes, and behaviours towards such strategies.     

The role of alternative splicing in controlling non-ionotropic signalling of N-methyl-D-aspartate receptors of the central nervous system

Posted on 18-11-2021 — N-methyl-D-aspartate receptors (NMDARs) are receptors in the central nervous system (CNS) known for their role in disease, plasticity and neuronal development. They are made up of two glycine-binding GluN1 subunits and two glutamate-binding GluN2 subunits. Typically, NMDARs signal ionotropically (with ion influx), however increasing evidence suggests that these receptors also signal non-ionotropically, or metabotropically. This occurs through glycine binding on the GluN1 subunits, but the molecular control of non-ionotropic signaling in NMDARs remains unknown. The GluN1 subunit comprises of eight alternatively spliced isoforms produced by the inclusion or exclusion of N1 and the C1, C2, C2’ polypeptide cassettes. Given the diversity that exists in GluN1 isoforms within the CNS and the role that differential splicing has on hippocampal long-term potentiation, UTCSP scientist Dr. Michael Salter and colleagues investigated whether alternative splicing of GluN1 would affect non-ionotropic signaling of NMDARs on hippocampal neurons. To do this, they examined glycine-induced signaling with all eight splice isoforms of GluN1 with heterologously expressed NMDARs in mice; representative isoforms in mice engineered to express only GluN1a (lacking N1 cassette) or GluN1b (containing N1 cassette) variants, and wild-type mice (WT).

Sex Specific Subgenual Anterior Cingulate Cortex Abnormalities in Chronic Pain Conditions Prevalent in the Opposite Sex

Posted on 15-09-2021 — The subgenual anterior cingulate cortex (sgACC) is known for its importance within the descending pain modulation (DPM) pathway, through its interconnectivity with other key parts of the DPM pathway and role in endogenous opioidergic pain inhibition. Previous work using fMRI and MEG in the Davis Lab has shown abnormalities within the sgACC across different chronic pain conditions. More specifically, it has been demonstrated that the sgACC has abnormal functional connectivity (FC) in women but not men, in a male prevalent chronic pain condition (Ankylosing Spondylitis). Carpel Tunnel Syndrome (CTS) is a neuropathic pain condition characterized by pain, numbness and tingling in the hands, due to damage caused by compression of the median nerve of the wrist. To complement their work observing sgACC FC in a male dominant chronic pain condition, the aim of this study was to characterize sgACC activity in CTS, which is a female prevalent chronic pain condition. The goal was to observe whether abnormal sgACC FC is characteristic of women with chronic pain or found in individuals that have a chronic pain condition that is more prevalent in the opposite sex.

Pain relief from trigeminal neuralgia reverses hippocampal abnormalities

Posted on 18-08-2021 — Memory and concentration difficulties are some of the frequently reported difficulties that chronic pain patients face. Recent evidence points to the hippocampus as the affected region in chronic pain that may result in these symptoms, as the hippocampus is involved in memory consolidation, behaviour regulation, and stress modulation.

The role of rostral ventromedial medulla ON and OFF cells in nociceptive behaviour in multiple body regions

Posted on 12-07-2021 — The rostral ventromedial medulla (RVM) is known to play a role in the endogenous modulation of nociceptive transmission in the central nervous system (CNS), within both spinal cord and trigeminal nociceptive pathways. It is thought that descending controls that are exerted by the RVM have a modulatory effect on pain sensations. In rats, neurons in the RVM have been classified as ON-cells, OFF-cells or NEUTRAL cells based on whether they elicit a tail flick response, with ON cells facilitating and OFF-cells inhibiting this nociceptive response. There has been evidence that has also shown that ON and OFF cell activity facilitate the activity of spinal dorsal horn (SDH) and medullary dorsal horn (MDH) neurons, and thereby underlie a potential important role of the RVM in endogenous pain control. However, the contribution and neural activity patterns of ON and OFF cells in relation to craniofacial nociceptive behaviours has not been explored in-depth.  In this study, UTCSP scientists Dr. Barry Sessle, Dr. Jonathon Dostrovsky and colleagues aimed to uncover whether RVM neuronal activity is related to noxious heat-induced craniofacial nociceptive behaviour, specifically jaw motor response, and compare it to other regions such as the tail.

A novel role for T-type calcium channels in the spinal cord in pain processing

Posted on 07-06-2021 — T-type channels have been implicated in pain processing in numerous previous studies using rodent models of chronic pain. T-type calcium channels are low voltage-activated calcium channels, contributing to subthreshold excitability of neurons. These channels are upregulated in peripheral sensory neurons during chronic pain. However, recent studies found that administration of T-type channel antagonists that are peripherally-restricted were ineffective in reversing pain hypersensitivity.

The Multifaceted Pain Experiences of those who have undergone Female Genital Cutting (FGC)

Posted on 10-05-2021 — Female Genital Cutting (FGC) (also known as female genital mutilation and female genital circumcision) is a rite of passage practiced in many different parts of the world. Around 2 million girls have FGC every year, and in total about 200 million women have had FGC worldwide. There are generally 3 different forms of FGC. Type 1 involves cutting the clitoral hood. Type 2 involves removal of the labia minora and glans clitoris. Type III includes removal of all previously mentioned regions, and the medial portion of the labia majora and infibulation.

Cage-lid hanging duration as a novel measurement of pain in mice

Posted on 12-04-2021 — Even though chronic pain is a prevalent problem that many Canadians and people around the world suffer with, there has been little progress in effective treatment development for this condition. One of the potential reasons for this is that the functional outcome measurements of pain behaviour in pre-clinical rodent models may not be representative of the pain experience of human patients

Digital app can help chronic pain sufferers manage their pain

Posted on 08-03-2021 — Toronto (March 4, 2021) - For the first time, an app has been shown to reduce key symptoms of chronic pain. A UHN-led study evaluated the impact of Manage My Pain (MMP), a digital health solution developed by ManagingLife, on patients seen at the Iroquois Falls Family Health Team, and the Toronto Western and Toronto General Hospitals.

Nerve transfers or tendon transfers for radial nerve injuries: which is better?

Posted on 08-03-2021 — Radial nerve injuries are very common and can become a painful and disabling condition. Current treatment methods for radial nerve injury include reconstructive options such as tendon or nerve transfers. Most studies to date have focused on patient outcomes from tendon transfers, but not nerve transfers. This study by UTCSP scientist Dr. Christine Novak and colleagues aims to augment current literature and compare tendon transfer and nerve transfer outcomes in their ability to restore radial nerve function. It was hypothesized that both techniques would improve function and patient satisfaction but would vary in their advantages.

Mice display social transmission of pain through physical contact

Posted on 09-02-2021 — Empathy, defined as the ability to understand, share, and respond to the emotional states of others, is considered a critical process for promoting attachment and long-term stability of social bonds. Empathetic behaviours are evolutionarily conserved among species and can range from simple, such as emotional contagion, to complex, such as perspective taking. Although empathy has been shown to be important in social structures, how empathy is established between individuals and the role of physical touch in empathy development remains unknown.

Myofascial Pain Syndrome is Associated with Lower Insulin-Like Growth Factor-2 Levels

Posted on 10-01-2021 — Myofascial pain syndrome (MPS) is a musculoskeletal chronic pain disorder with pathological contraction of localized muscle fibers, resulting in local and referred pain. MPS is often caused by muscle injury or damage. Insulin-like growth factors, IGF-1 and IGF-2, are hormones that regulate muscle growth, differentiation, as well as muscle maintenance and repair. Pain resulting from MPS is thought to be due to biochemical changes at peripheral nociceptive neurons and IGF-1 has also been implicated in the nociceptive pathway. However, the role of IGF-2 has yet to be implicated in pain and whether IGFs contribute to MPS specifically have not been extensively investigated.