Spinal Cord Injury Pain: Understanding Mechanisms To Develop Treatments
Funder
National Health and Medical Research Council
Funding Amount
$597,675.00
Summary
Spinal cord injury has devastating effects on health and quality of life. Many of the major consequences of injury, such as chronic pain and loss of voluntary voiding, are "invisible" – i.e., they are not as visible as limitations of mobility. Our study aims to define the neurobiological changes that cause development of persistent pain after spinal cord injury and use pharmacological tools to attenuate the development of pain.
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
Training-induced Restoration Of Topographic Maps And Vision During Opticnerve Regeneration
Funder
National Health and Medical Research Council
Funding Amount
$379,725.00
Summary
The mature brain and spinal cord, or central nervous system (CNS), are extremely complex. A consequence of such complexity is that little if any spontaneous repair or regeneration occurs after damage. Brain injury and para- or quadriplegia thus inflict extremely high costs on the individual and to society, estimated at approximately $1 billion annually in Australia. One of the greatest medical challenges therefore is to restore function following neurotrauma. One of the most exciting advances, h ....The mature brain and spinal cord, or central nervous system (CNS), are extremely complex. A consequence of such complexity is that little if any spontaneous repair or regeneration occurs after damage. Brain injury and para- or quadriplegia thus inflict extremely high costs on the individual and to society, estimated at approximately $1 billion annually in Australia. One of the greatest medical challenges therefore is to restore function following neurotrauma. One of the most exciting advances, however, over the last decade is the recognition that the adult CNS, particularly after damage, does have a capacity for repair and that appropriate neural activity, produced either via relevant experience or specific training, is essential in driving the repair process to produce useful behavioural recovery. One of the clearest examples comes from our laboratory in which we have recently shown that training animals on specific visual tasks during optic nerve regeneration allows useful vision to be restored; untrained animals are blind via the experimental eye. The advantage of the visual system is that it is a relatively simple part of the CNS with one major class of nerve cell projecting to well defined and accessible brain regions. The significance of the project is that, for the first time, we are able pinpoint specific training-induced effects within identified nerve cells and their connections, a task that is much harder within other CNS regions. In particular, we will examine molecular, anatomical and functional changes that are induced via training and explore whether intervention with blockers of inhibitory neurotransmission further improves the beneficial effects of training. Understanding the changes in nerve cells that underlie the positive effects of training after neurotrauma will have implications for the continuing development of rehabilitation strategies for improved recovery after CNS injury.Read moreRead less
We use a mouse model of inflammatory bowel disease (IBD) to determine how sensations from the inflamed gut are processed in the spinal cord. Over 60,000 Australians suffer from IBD and debilitating pain is a major symptom. Surprisingly, we know very little about how pain signals originating in the normal or the diseased gut are organised and processed in the central nervous system. Obtaining such information is a necessary first step before we can develop therapies to relieve gut pain.
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
Development Of Peripheral Sensory Pathways In Humans
Funder
National Health and Medical Research Council
Funding Amount
$477,504.00
Summary
To receive the appropriate information about the state of our muscles, joints, organs, and skin we need a properly 'connected' sensory system. Recent evidence suggests traumatic events during early development can alter sensory connections within the spinal cord. This can lead to debilitating movement disorders, digestive diseases, and increased pain. In this study we will examine how peripheral sensory fibres connect with the appropriate nerve cells in the human spinal cord during development.
Although chronic pain is a serious clinical problem, treatments for its alleviation have largely failed, in part because they have not been tailored to the specific origin of the pain. This proposal focuses on rheumatoid arthritis, a common and incurrable source of chronic pain. This study will investigate how specific changes in spinal cord nerve cells contribute to chronic arthritic pain. The outcomes will help identify new targets to treat chronic pain in rheumatoid arthritis.
Understanding The Role Of Regulatory T Cells In Chronic Pain Following Nerve Injury
Funder
National Health and Medical Research Council
Funding Amount
$587,046.00
Summary
Neuropathic pain is a debilitating condition of chronic pain that develops after damage to the nervous system, and lacks an effective treatment. This project focuses on the novel hypothesis that the immunosupressive regulatory T cells and their mediators play a critical role in controlling neuroinflammation and pain hypersensitivity following peripheral nerve injury. This study promises to enhance our understanding of the neuroimmune activation in neuropathic pain and offers novel approaches for ....Neuropathic pain is a debilitating condition of chronic pain that develops after damage to the nervous system, and lacks an effective treatment. This project focuses on the novel hypothesis that the immunosupressive regulatory T cells and their mediators play a critical role in controlling neuroinflammation and pain hypersensitivity following peripheral nerve injury. This study promises to enhance our understanding of the neuroimmune activation in neuropathic pain and offers novel approaches for pain management.Read moreRead less
Deciphering The Mechanisms For Constructing The Olfactory System
Funder
National Health and Medical Research Council
Funding Amount
$496,321.00
Summary
The olfactory (smell) system is a unique part of the nervous system; nerve cells are generated throughout life and it can regenerate even after injury. It therefore provides an excellent model for examining the growth, development and maintenance of nerve cells. This project will examine the effects on the organisation of the olfactory system when some guidance signals are altered. Information we obtain about how this system develops and regenerates may be useful in treating brain disorders and ....The olfactory (smell) system is a unique part of the nervous system; nerve cells are generated throughout life and it can regenerate even after injury. It therefore provides an excellent model for examining the growth, development and maintenance of nerve cells. This project will examine the effects on the organisation of the olfactory system when some guidance signals are altered. Information we obtain about how this system develops and regenerates may be useful in treating brain disorders and spinal injuries The results of these experiments will provide important information on the the initial growth and targeting of these nerve cells which may have implications for regeneration of these as well as other nerve cells.Read moreRead less
THE AUTONOMIC, SOMATIC AND CENTRAL NEURAL RESPONSES TO DEEP AND SUPERFICIAL PAIN IN HUMAN SUBJECTS
Funder
National Health and Medical Research Council
Funding Amount
$375,750.00
Summary
Pain is a subjective experience, the intensity of which can be readily influenced by personal experience. Despite this, pain originating from a particular part of the body will usually be described by all individuals as having similar character. For example, pain arising from the skin is commonly described as being sharp or burning and is usually easy to localise, whereas pain arising from muscle is commonly dull, throbbing and diffuse. In addition to producing sensory changes, pain also evokes ....Pain is a subjective experience, the intensity of which can be readily influenced by personal experience. Despite this, pain originating from a particular part of the body will usually be described by all individuals as having similar character. For example, pain arising from the skin is commonly described as being sharp or burning and is usually easy to localise, whereas pain arising from muscle is commonly dull, throbbing and diffuse. In addition to producing sensory changes, pain also evokes changes in blood pressure, heart rate and motor activity (often in an attempt to remove the source of the pain). The proposed research aims to characterise the cardiovascular and motor patterns associated with pain originating in skin and in muscle and to examine the brain regions that produce these changes. More specifically, microelectrodes will be used to investigate changes in peripheral nerve activity during transient painful skin and muscle events in awake human subjects. In a separate investigation functional magnetic resonance imaging will be used to determine brain sites that are activated by skin or muscle pain.Read moreRead less