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
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