Peripheral Mechanims Of Analgesia In Inflammatory Pain
Funder
National Health and Medical Research Council
Funding Amount
$181,018.00
Summary
This proposal will explore for the first time the interaction between the peripheral nervous system and the immune system and the effect on pain. Our preliminary studies highlight the direct interaction between the immune system and the nervous system as having an integral role in the control of pain in inflammation. Indeed these studies emphasis the impact of a compromised immune system on this inflammatory pain.
Opioid Actions On Sensory Neuron Excitability In Vitro
Funder
National Health and Medical Research Council
Funding Amount
$241,018.00
Summary
Morphine and related drugs are very widely used for pain relief, although the way they affect the pain-sensitive cells in the body is not well understood. Use of morphine for extended periods of time often makes morphine less effective for pain relief, which makes it necessary to increase the dose of morphine given. This leads to an increase in the unwanted side effects of morphine, and can eventually lead to morphine becoming ineffective in controlling pain. This study is designed to examine ho ....Morphine and related drugs are very widely used for pain relief, although the way they affect the pain-sensitive cells in the body is not well understood. Use of morphine for extended periods of time often makes morphine less effective for pain relief, which makes it necessary to increase the dose of morphine given. This leads to an increase in the unwanted side effects of morphine, and can eventually lead to morphine becoming ineffective in controlling pain. This study is designed to examine how morphine affects pain-sensitive cells, and to determine how continued use of morphine changes the way pain-sensitive cells respond to morphine. We hope that by understanding how morphine works on pain-sensitive cells, we can understand why it does not work so well after continued use. This information should enable us to design better forms of pain relief than we have now.Read moreRead less
A group of nerves, called sensory nerves, supply most body organs including the uterus, and are well known to transmit information to the brain. It is now known that these nerves are also capable of releasing the chemicals (neuropeptides) from their endings within these body organs to affect their function. In the uterus these chemicals cause the uterus to contract. We have shown that neuropeptides known as tachykinins are effective in lower concentrations when applied to small specimens of uter ....A group of nerves, called sensory nerves, supply most body organs including the uterus, and are well known to transmit information to the brain. It is now known that these nerves are also capable of releasing the chemicals (neuropeptides) from their endings within these body organs to affect their function. In the uterus these chemicals cause the uterus to contract. We have shown that neuropeptides known as tachykinins are effective in lower concentrations when applied to small specimens of uterine tissue taken from non-pregnant women at hysterectomy than when applied to similar uterine specimens taken from pregnant women at caesarean section. The aim of this project is twofold. Firstly, we want to know why the tachykinins are more potent in uterine tissue from non-pregnant women. Possible explanations that we will examine are that tissues from non-pregnant women contain more sites of action at which the peptides can act, or alternatively, that there is decreased breakdown of these tachykinins in uterine tissue from non-pregnant women. This could occur if a substance known to break down the tachykinins in the uterus shows greater activity during pregancy than when a woman is not pregnant. Secondly, we wish to find out if other chemicals (substances that can produce inflammatory responses, and in particular a group of chemicals known as prostaglandins), that are known to be present in greater amounts in the tissues of women during disease states such as dysmenorrhoea, can cause the release of the neuropeptides that we are studying. If they do cause such a release of tachykinins, this could be an important factor contributing to the disease state. Our hypothesis is that tachykinins and the substances which can break them down may play an important role in regulating uterine contractility in non-pregnant and to a lesser degree in pregnant women.Read moreRead less
Opioid Actions On Identified Sensory Neurons In Vitro
Funder
National Health and Medical Research Council
Funding Amount
$371,850.00
Summary
Opioids (in particular morphine) are the gold standard drugs for the relief of most types of moderate to severe pain. Despite the effectiveness of opioids and other analgesics, many people still suffer unrelieved pain. There are 2 main reasons for this. Firstly, there are some types of pain that are refractory to currently used analgesics from the outset, and secondly, chronic conditions may require escalating doses of analgesics for adequate pain relief, and these does may increase until side e ....Opioids (in particular morphine) are the gold standard drugs for the relief of most types of moderate to severe pain. Despite the effectiveness of opioids and other analgesics, many people still suffer unrelieved pain. There are 2 main reasons for this. Firstly, there are some types of pain that are refractory to currently used analgesics from the outset, and secondly, chronic conditions may require escalating doses of analgesics for adequate pain relief, and these does may increase until side effects become intolerable. My studies will provide insight into the reasons that underlie the differential effectiveness of opioids in acute pain conditions, as well as the reasons why opioids lose their effectiveness over time. These studies will also identify molecular targets that may be important for developing analgesics for specific pain conditions. Because the head is the source of many familiar painful conditions, including tooth pain, migraine and temporomandibular disorders, I will be using neurons from the trigeminal ganglion, the part of the nervous system which supplies the sensory innervation to the structures involved in these pain states. By using mice as experimental animals, I will be able to investigate the contribution of neurons that innervate specific parts of the head to these pain states, and study how chronic morphine treatment affects the behavior of these cells. I hope that these studies will provide a basis for designing strategies that improve the effectiveness of existing analgesics, and perhaps lead to the identification of new, better pain relievers.Read moreRead less
Mechanisms Of Opioid Receptor Desensitisation In Single Neurons
Funder
National Health and Medical Research Council
Funding Amount
$301,320.00
Summary
Opioid drugs including morphine and codeine are the most effective analgesics known but their utility is limited by problems of tolerance (which is the need for increasing doses of drug to achieve the same effect), physical dependence characterised by a debilitating withdrawal syndrome on cessation of use, and addiction or compulsive drug seeking and use. Better understanding of the mechanisms underlying these adverse processes could lead to the development of more acceptable pain relieving agen ....Opioid drugs including morphine and codeine are the most effective analgesics known but their utility is limited by problems of tolerance (which is the need for increasing doses of drug to achieve the same effect), physical dependence characterised by a debilitating withdrawal syndrome on cessation of use, and addiction or compulsive drug seeking and use. Better understanding of the mechanisms underlying these adverse processes could lead to the development of more acceptable pain relieving agents. This project will increase understanding of the initial molecular events occurring in nerve cells that are believed to underlie the development of tolerance and physical dependence on opioid drugs. These studies will focus on sensory nerve cells isolated and cultured from animals, which are one of the major targets of pain relieving drugs. Understanding of these processes will lead to development of better strategies to avoid development of tolerance and perhaps physical dependence. They will also identify on a molecular level the mechanisms that determine why one opioid drug may produce more tolerance than another. This knowledge may lead to the development of pain relieving drugs that do not so readily lose their effectiveness in the management of chronic pain.Read moreRead less
Metabotropic Glutamate Receptors: Pharmacological Studies Of Receptor Subtypes In Neuronal Injury.
Funder
National Health and Medical Research Council
Funding Amount
$145,770.00
Summary
Glutamate is the major transmitter of excitatory information in the mammalian brain. Disruption of glutamate-mediated signaling between brain cells results in high extracellular levels of glutamate which is toxic to neurones. A recently discovered family of signal transducers, the metabotropic glutamate receptors, has been found to be localized on neurones and is switched on by these toxic glutamate levels. The roles of these metabotropic glutamate receptors in neurotoxicity is essentially unexp ....Glutamate is the major transmitter of excitatory information in the mammalian brain. Disruption of glutamate-mediated signaling between brain cells results in high extracellular levels of glutamate which is toxic to neurones. A recently discovered family of signal transducers, the metabotropic glutamate receptors, has been found to be localized on neurones and is switched on by these toxic glutamate levels. The roles of these metabotropic glutamate receptors in neurotoxicity is essentially unexplored and is the topic under investigation in this project. How their activation affects cellular signaling switch on will be investigated to gain an understanding of the roles metabotropic glutamate receptors play in acute brain injury (eg stroke) and chronic neurodegenerative conditions (eg Huntington's chorea and Alzheimer's disease).Read moreRead less
Pharmacological Modulation Of Microglial Responses After Transient Forebrain Ischaemia In Rats
Funder
National Health and Medical Research Council
Funding Amount
$170,906.00
Summary
A stroke is caused by an acute blockade of blood flow to a brain region and is normally caused by a clot in the artery that supplies blood to that region. Within minutes, the region of the brain that is receiving no blood flow, dies and so the functions controlled by that region cease. If this region controls key functions such as breathing then the patient dies and this occurs in about one third of patients. However, in the majority of patients, the blockage affects parts of the brain controlli ....A stroke is caused by an acute blockade of blood flow to a brain region and is normally caused by a clot in the artery that supplies blood to that region. Within minutes, the region of the brain that is receiving no blood flow, dies and so the functions controlled by that region cease. If this region controls key functions such as breathing then the patient dies and this occurs in about one third of patients. However, in the majority of patients, the blockage affects parts of the brain controlling movement of limbs or speech and so these patients suffer permanent disabilities. Not surprisingly, stroke is the most common life-threatening neurological disease and the major cause of disability in adults over 45. Apart from the profound effect stroke has on the patient and the family, the annual cost of disability to the Australian community is approx $ 1 billion. If the disability could be minimised by reducing institutionalization then the cost saving would be great. Research is being carried out to define how nerves die when they have insufficient blood supply and progress has been made in understanding the biochemical basis of this process. Such knowledge opens the way for the design of novel drugs to delay nerve death. Our laboratory has been successful in designing a novel drug, AM-36 that minimises nerve death in the forebrain of rats that have had the blood supply to the forebrain interrupted for 3 to 5 hours. A recent report has shown that a stroke in the forebrain can lead to nerve damage in the spinal cord and this could contribute to impaired walking in stroke patients. This is an unexpected finding and this project seeks to define how and when nerves in the spine die after a stroke in the forebrain. Such information should then lead to the rational design of drugs to minimise the death of nerves in the spinal cord as well as in the forebrain.Read moreRead less