Mechanisms Of Endogenous Cannabinoid Mediated Analgesia Within The Midbrain
Funder
National Health and Medical Research Council
Funding Amount
$518,820.00
Summary
While opioid analgesics such as morphine are the most important drugs used to treat moderate to severe pain, their usefulness is limited by side effects such as tolerance and respiratory depression. In addition, clinically relevant neuropathic chronic pain syndromes (caused by nervous system damage) are relatively resistant to opioids. Animal studies have shown that the active ingredient of the plant Cannabis sativa, THC, and a number of synthetic cannabinoids are analgesic in acute pain models, ....While opioid analgesics such as morphine are the most important drugs used to treat moderate to severe pain, their usefulness is limited by side effects such as tolerance and respiratory depression. In addition, clinically relevant neuropathic chronic pain syndromes (caused by nervous system damage) are relatively resistant to opioids. Animal studies have shown that the active ingredient of the plant Cannabis sativa, THC, and a number of synthetic cannabinoids are analgesic in acute pain models, and interestingly, in chronic neuropathic pain models. Unfortunately, cannabinoid also produce a spectrum of adverse side-effects. Administered cannabinoids such as THC produce their physiological effects by mimicking the actions of the body's own cannabinoids (endocannabinoids) by activating cell-surface proteins, called cannabinoid receptors. The endocannabinoid neurotransmitter system is emerging as a potential therapeutic target. For example, it has recently been shown that analgesia induced by physiological stressors is partly mediated by endocannabinoids within the brain. In addition, novel endocannabinoid breakdown inhibitors have some efficacy in animal models of anxiety and chronic pain. Several brain regions are known to play a pivotal role in the analgesic actions of exogenous and endogenous cannabinoids. In previous studies I have identified the cellular mechanisms by which exogenously applied opioids and cannabinoids produce their analgesic effects in single brain cells. However, the mechanisms of endocannabinoid actions within these brain regions are unknown. The proposed study will determine the cellular actions of endogenously released cannabinoids in normal animals and in chronic pain states. Parallel studies will examine the effect of modulation of the endocannabinoid system in animal models of pain. These techniques have the potential to identify novel endocannabinoid analgesic pharmacotherapies with enhanced efficacy and reduced side effects.Read moreRead less
Chronic pain affects 1 in 5 Australians and neuropathic pain is among the most severe forms of chronic pain. Several peptides derived from cone snail venoms have attracted recent attention as potential therapeutic agents for the treatment of neuropathic pain. One of these, conotoxin MVIIA, has recently been approved in the US and Europe and others, including CVID and ACVI, are in various stages of clinical investigation. These small disulfide rich peptides share the attractive features of peptid ....Chronic pain affects 1 in 5 Australians and neuropathic pain is among the most severe forms of chronic pain. Several peptides derived from cone snail venoms have attracted recent attention as potential therapeutic agents for the treatment of neuropathic pain. One of these, conotoxin MVIIA, has recently been approved in the US and Europe and others, including CVID and ACVI, are in various stages of clinical investigation. These small disulfide rich peptides share the attractive features of peptides in general of having exquisite selectivity for particular receptors, but also share the general disadvantages of peptides of short biological half-lives and poor bioavailablility. Stabilisation of these conotoxins has the potential to substantially increase their therapeutic potential. In preliminary studies we have shown that by introducing a circular petide backbone into a conotoxin using a linker sequence we can increase its stability and resistance to enzymatic degradation. We therefore propose that it will be possible to cyclise a wide range of conotoxin molecules and thereby improve their drug like properties. In this project we will use our cyclisation approach to develop new potential treatments for pain from two classes of conotoxins. One of the lead molecules shows oral bioavailability in an animal pain model and potentially represents a major breakthrough in the field of peptide drug delivery.Read moreRead less
Molecular And Cellular Basis For The Analgesic Properties Of N-Arachidonyl Amino Acids
Funder
National Health and Medical Research Council
Funding Amount
$509,017.00
Summary
Chronic pain affects 20% of the population of Australia, but current treatments for chronic pain are often problematic. A recently described class of compounds, the arachidonyl amino acids, show particular promise as analgesic agents, but at present there is very little understanding of how these compounds mediate their analgesic effects. In this project we will apply a variety of molecular, cellular and behavioural approaches to understand how the arachidonyl amino acids provide pain relief.
Allosteric Regulation Of G Protein-coupled Receptors
Funder
National Health and Medical Research Council
Funding Amount
$509,017.00
Summary
The normal function of all living cells depends on how they respond to the multitude of physical and chemical stimuli to which they are constantly exposed. The majority of these stimuli acting on cells do so not by directly entering the cells, but rather by acting on specific types of receiver proteins on the cell's surface that are called receptors. The most important family of cell-surface receptors transmit their message to the inside of the cell by coupling to yet another type of protein kno ....The normal function of all living cells depends on how they respond to the multitude of physical and chemical stimuli to which they are constantly exposed. The majority of these stimuli acting on cells do so not by directly entering the cells, but rather by acting on specific types of receiver proteins on the cell's surface that are called receptors. The most important family of cell-surface receptors transmit their message to the inside of the cell by coupling to yet another type of protein known as a G protein, and are therefore commonly referred to as G protein-coupled receptors (or GPCRs). Aberrations in the normal function of these GPCRs have been implicated in a wide variety of disorders, including neuropsychiatric conditions, endocrine disorders, cardiovascular disease and many cancers. To date, the majority of drugs acting at GPCRs do so by binding to specific regions on these receptors. Although many breakthroughs in disease treatment have been achieved using this approach, there remain a number of acknowledged limitations, including lack of drug selectivity, toxicity and reduced responsiveness with prolonged therapy. Our current proposal focuses on targeting drugs to alternative regions of GPCRs that may overcome many of the limitations associated with current drug therapies. An understanding of the properties of these alternative drug binding sites, which will be investigated in our current grant, can lead to more effective treatments for a variety of diseases.Read moreRead less
A major obstacle to the development of safer and more effective pain treatments is the poorly defined nature of the different pathways involved in chronic pain. The applicant team bring together a unique set of research expertise in using neurotoxins to define, at the molecular level, how the nervous system functions. The applicants also share a common interest in understanding and improving treatments for pain, especially chronic pain which continues to remain poorly managed Through a focus on ....A major obstacle to the development of safer and more effective pain treatments is the poorly defined nature of the different pathways involved in chronic pain. The applicant team bring together a unique set of research expertise in using neurotoxins to define, at the molecular level, how the nervous system functions. The applicants also share a common interest in understanding and improving treatments for pain, especially chronic pain which continues to remain poorly managed Through a focus on pain research, the Program will significantly enhance the scope of existing multidisciplinary collaborations between the Cis Lewis Alewood, Adams and Christie, which have already made a considerable impact in the fields of pharmacology and neuroscience. The CIs also have considerable experience in the development of pain therapeutics, having discovered two conopeptides now under commercial development with AMRAD (AM336) and Xenome Ltd (Xen2174). This Program will discover and use highly selective conopeptides such as these to dissect the pharmacology of peripheral pain pathways and their projections into the central nervous system, and to identify and characterise new targets amenable to drug intervention. The long-term goal of the Program is to discover new targets in pain pathways and develop conopeptides that act on these targets in animal models of chronic pain. These molecules will be optimised within the Program to the point where they can be considered for pre-clinical development in collaboration with commercial partners.Read moreRead less