Understanding The Role Of Nociceptin In PMNL-mediated Inflammation In Vivo
Funder
National Health and Medical Research Council
Funding Amount
$474,750.00
Summary
This work will study the role of a type of protein in white blood cell movement into tissues, a process called inflammation. The outcome of this work may lead to the development of molecules which control this movement of white blood cells more specifically than existing therapeutics. Such inhibitors would potentially be useful as anti-inflammatory agents in a range of human diseases.
Mechanisms Controlling The Excitability Of Corneal Nociceptor Nerve Terminals
Funder
National Health and Medical Research Council
Funding Amount
$364,759.00
Summary
The project uses a new approach that allows, for the first time, electrical activity to be recorded and analysed from the very fine nerve endings of nerves whose activation results in painful sensations. Using this technique the mechanisms by which substances released in damaged and inflamed tissues lead to discharge of action potentials and the sensation of pain will be investigated. In particular the project investigates the role of a population of sodium ion selective pores (channels) that ar ....The project uses a new approach that allows, for the first time, electrical activity to be recorded and analysed from the very fine nerve endings of nerves whose activation results in painful sensations. Using this technique the mechanisms by which substances released in damaged and inflamed tissues lead to discharge of action potentials and the sensation of pain will be investigated. In particular the project investigates the role of a population of sodium ion selective pores (channels) that are uniquely expressed in pain sensing nerves. These channels have been hypothesised to play an important role in determining the behaviour of these nerves. In addition, the project investigates how some substances released in inflamed tissues sensitize pain sensing nerves, causing them to more readily discharge action potentials. This change is the major cause of pain associated with inflammatory diseases such as arthritis. In summary, the proposed project will provide new insight into how pain sensing nerves function. This knowledge is essential for the development of more effective strategies for treating pain resulting from inflamed and damaged tissue.Read moreRead less
Does The Complement System Contribute To Neuropathic Pain?
Funder
National Health and Medical Research Council
Funding Amount
$262,958.00
Summary
Nerve injury often results in increased sensitivity to painful stimuli and the perception of innocuous stimuli as painful; it may also result in spontaneous pain. These disorders of pain sensation due to nerve injury are common, debilitating and difficult to treat. They are symptoms of neuropathic pain. Pain is normally signalled to the brain by sensory nerve cells called nociceptors. Following nerve injury, nociceptors are sensitised by chemicals released by inflammatory cells. This contributes ....Nerve injury often results in increased sensitivity to painful stimuli and the perception of innocuous stimuli as painful; it may also result in spontaneous pain. These disorders of pain sensation due to nerve injury are common, debilitating and difficult to treat. They are symptoms of neuropathic pain. Pain is normally signalled to the brain by sensory nerve cells called nociceptors. Following nerve injury, nociceptors are sensitised by chemicals released by inflammatory cells. This contributes to neuropathic pain. We have evidence that inflammatory responses play a key role in initiating neuropathic pain. Other evidence suggests that the immune system contributes to neurological diseases and accompanying pain (e.g. Guillain-Barr syndrome and multiple sclerosis). We plan to test the idea that a component of the immune system known as the complement pathway contributes to the development of neuropathic pain following peripheral nerve injury. The outcome of this work will be a better understanding of the way in which nerve injury leads to chronic disorders of pain, including increased sensitivity to painful stimuli. This will lead in turn to the development of more effective treatments for neuropathic pain.Read moreRead less
The Role Of Proinflammatory Interleukin-17 (IL-17) And IL-17-producing T Cells In Neuropathic Pain
Funder
National Health and Medical Research Council
Funding Amount
$470,051.00
Summary
Peripheral nerve injury often results in persistent and debilitating neuropathic pain. My overall objective is to understand the immunological mechanisms responsible for such pain. I plan to test the hypothesis that the proinflammatory cytokine interleukin-17 promotes neuroinflammation and contributes to increased pain sensitivity after nerve injury. This study promises to enhance our understanding of neuroimmune activation in neuropathic pain and offers new opportunities for pain management.
Opioids are the most important drugs used to treat moderate to severe pain, however the development of tolerance limits their usefulness. In addition, clinically important pain states, particularly neuropathic pain, are insensitive to opioid treatment. Human and animal studies indicate that the active ingredient of the plant cannabis sativa, THC, and a number of synthetic cannabinoids also have analgesic, or pain relieving properties. Of particular interest is the finding that cannabinoids enhan ....Opioids are the most important drugs used to treat moderate to severe pain, however the development of tolerance limits their usefulness. In addition, clinically important pain states, particularly neuropathic pain, are insensitive to opioid treatment. Human and animal studies indicate that the active ingredient of the plant cannabis sativa, THC, and a number of synthetic cannabinoids also have analgesic, or pain relieving properties. Of particular interest is the finding that cannabinoids enhance the analgesic actions of opioids. Several brain regions are known to play a pivotal role in the analgesic actions of both opioids and cannabinoids. In previous studies I have identified the cellular and molecular mechanisms by which opioid drugs produce their analgesic effects in single brain cells. However, the cellular mechanisms underlying cannabinoid induced analgesia within the brain are poorly understood. In addition, the cellular actions of cannabinoids and opioids in neuropathic pain states are unknown. The proposed study will determine the cellular and molecular mechanisms underlying the analgesic actions of cannabinoids and opioids in single brain neurons in normal and neuropathic pain states. These techniques have the potential to identify antinociceptive combinations between cannabinoids and other agents with enhanced efficacy and reduced side effects.Read moreRead less
Synergism Between Opioids And Other Agents At Central Primary Afferent Synapses
Funder
National Health and Medical Research Council
Funding Amount
$202,771.00
Summary
Opioids, such as codeine, pethidine and morphine, are the most effective pain relieving drugs known but their clinical utility is limited by hazardous and potentially lethal side effects, as well as the development of tolerance and physical dependence with associated addiction liability. Recent research in our laboratory has identified for the first time a mechanism in the mammalian brain by which the pain relieving actions of opioids can be greatly enhanced by drugs that independently modulate ....Opioids, such as codeine, pethidine and morphine, are the most effective pain relieving drugs known but their clinical utility is limited by hazardous and potentially lethal side effects, as well as the development of tolerance and physical dependence with associated addiction liability. Recent research in our laboratory has identified for the first time a mechanism in the mammalian brain by which the pain relieving actions of opioids can be greatly enhanced by drugs that independently modulate biochemical processes distinct from those altered by opioids. Exploitation of these mechanisms has great potential for the development of new pharmacotherapies for effective pain relief with minimised side effects. These synergistic mechanisms appear to be at least as important for pain relief in the spinal cord as in brain, so the proposed studies will first examine the basis for synergism with opioid mediated pain relief in spinal cord. There is also strong evidence that the mechanisms to be studied in the proposed work are pivotal in the development of debilitating, chronic pain conditions that involve heightened sensitivity to painful stimuli and-or painful responses to normally innocuous stimuli such as light touch. Such aberrant responses can persist long after initial tissue damage has recovered. It is known that opioids can limit somewhat the initial steps in the induction of these abnormal responses but the mechanisms involved are unknown. The proposed studies will contribute to resolution of these mechanisms. Better understanding of the basis of these pathological processes will lead to better strategies for retarding or preventing the development of chronic pain conditions.Read moreRead less
Current treatments for chronic pain are limited in their success. This emphasises the need for new insights into the basic mechanisms and nervous system circuitry underlying altered or chronic pain states. Work in animals and patients with chronic pain shows that certain brainstem centres communicate, via descending spinal cord pathways, with small nerve cells in the superficial dorsal horn (SDH) of the spinal cord. These SDH neurones receive and process pain-signalling information from the skin ....Current treatments for chronic pain are limited in their success. This emphasises the need for new insights into the basic mechanisms and nervous system circuitry underlying altered or chronic pain states. Work in animals and patients with chronic pain shows that certain brainstem centres communicate, via descending spinal cord pathways, with small nerve cells in the superficial dorsal horn (SDH) of the spinal cord. These SDH neurones receive and process pain-signalling information from the skin and internal organs, and receive inputs from descending pathways. This descending input can either inhibit or enhance the activity of SDH neurones and subsequent pain perception. Till now it has been difficult to directly examine how descending pain pathways influence the small SDH neurones in the spinal cord. A new approach, which has been developed in our laboratory, now allows us to record from these very small SDH neurones in the spinal cord of an intact deeply anaesthetized mouse. In addition, our technique allows us to examine the recorded SDH neurone s responses to functionally relevant stimuli (brushing or pinching the hindpaw) as well as its physiology and anatomy. This project will use our new techniques to examine the effects of activating descending brainstem pathways that alter the way painful stimuli are processed in the spinal cord. The effects of altered levels of inhibition in the spinal cord will also be studied by using mice with naturally occurring mutations in their inhibitory glycine receptors. We believe a more complete understanding of pain processing mechanisms will be achieved by examining the role of descending pathways in an intact animal preparation. Such data are essential for the development of drug therapies that can successfully target pain syndromes.Read moreRead less