Protein Partners Of Rapsyn That Regulate Acetylcholine Receptor Clustering
Funder
National Health and Medical Research Council
Funding Amount
$411,000.00
Summary
Spinal nerves control our limb muscles by releasing chemical signals directly onto the surface of muscle fibres that they contact. These chemical signalling contacts are called synapses. They are like the synapses between nerve cells in our brains but easier to study, meaning that we can make more rapid progress in understanding how synapses work. The sensor receptors for chemical signals at the nerve-to-muscle synapse are held in place on the muscle fibre surface by a protein called rapsyn. In ....Spinal nerves control our limb muscles by releasing chemical signals directly onto the surface of muscle fibres that they contact. These chemical signalling contacts are called synapses. They are like the synapses between nerve cells in our brains but easier to study, meaning that we can make more rapid progress in understanding how synapses work. The sensor receptors for chemical signals at the nerve-to-muscle synapse are held in place on the muscle fibre surface by a protein called rapsyn. In turn, rapsyn must be organized by other chemical signals from the nerve, but we don't know exactly how this happens. When the receptors become disorganized at the synapse, in diseases such as Myasthenia Gravis, we lose control of our muscles. This project will employ newly developing techniques of proteomics and genomics to identify new proteins that bind to rapsyn and to test how they work to organize receptors at the synapse. By identifying the proteins that control rapsyn we may be able to develop new treatments for Myasthenia Gravis that restore the function of the synapse with less side effects than current therapies.Read moreRead less
Structural And Functional Consequences Of A Human Nicotinic Receptor Mutation
Funder
National Health and Medical Research Council
Funding Amount
$112,809.00
Summary
Identification of the defective gene underlying a particular form of inherited epilepsy in man, autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), now provides the first opportunity to study the basic mechanisms of an inherited epilepsy in man. The responsible mutations affect a subunit of the nicotinic acetylcholine receptor. In this research project, quantitative methods of imaging the brain will be used bridge the gap in understanding which lies between the molecular defect and the ....Identification of the defective gene underlying a particular form of inherited epilepsy in man, autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), now provides the first opportunity to study the basic mechanisms of an inherited epilepsy in man. The responsible mutations affect a subunit of the nicotinic acetylcholine receptor. In this research project, quantitative methods of imaging the brain will be used bridge the gap in understanding which lies between the molecular defect and the clinical manifestations of ADNFLE. Involvement of a system of nerve pathways, the mesocortical dopaminergic system, is postulated to explain the preferential susceptibility of the frontal lobe to seizures in ADNFLE. Positron emission tomography will be used to examine changes in neurotransmitter release in the frontal lobe. The molecular defect in ADNFLE also provides a unique opportunity to examine the role of the nicotinic receptor in the development of the human brain and in important aspects of human cognition. Statistical mapping of anatomical variability and high resolution magnetic resonance scans will be used to detect alterations in the anatomical structure of the mesial frontal lobe. Evidence of deficient nicotinic receptor-mediated cognitive effects in ADNFLE will be sought using a battery of psychological tests shown to be sensitive to the effects of nicotine.Read moreRead less
A Novel Knockin Model To Test The Role Of Nicotine Acting On Alpha4 Acetylcholine Receptors In Complex Behaviours
Funder
National Health and Medical Research Council
Funding Amount
$581,315.00
Summary
Cigarette smoking is the single largest preventable cause of death and disease in Australia and worldwide. Nicotine contained in tobacco products acts on brain nicotine receptors, which plays an intrinsic role in addiction. One type of receptor for nicotine found in regions of the brain associated with drug-seeking behaviour is called alpha4 nicotinic receptors. We have made a mouse with a mutation in this nicotine receptor to study nicotine addiction and anxiety.
Targeting Alpha-conotoxin MII To Inhibit Neuronal Nicotinic Acetylcholine Alpha3beta2 Receptors Of The CNS
Funder
National Health and Medical Research Council
Funding Amount
$218,334.00
Summary
Nicotinic acetylcholine receptors (nAChRs) play a central role in nerve signal transmission, neurite growth and development and are the representative model of the ligand-gated ion channel superfamily. Recent studies, including those from Dr Lewis' and A-Prof Alewood's laboratories, have identified alpha-conotoxin peptides which can discriminate among the different nAChRs, apparently by binding to the specific interfaces formed by different subunit combinations. Thus alpha-conotoxins are unique ....Nicotinic acetylcholine receptors (nAChRs) play a central role in nerve signal transmission, neurite growth and development and are the representative model of the ligand-gated ion channel superfamily. Recent studies, including those from Dr Lewis' and A-Prof Alewood's laboratories, have identified alpha-conotoxin peptides which can discriminate among the different nAChRs, apparently by binding to the specific interfaces formed by different subunit combinations. Thus alpha-conotoxins are unique tools with which to identify and determine the physiological role, played by the different native neuronal nAChRs. Moreover, they are unusually stable peptides and can withstand enzyme and acid treatment. These findings have encouraged us to pursue the viability of alpha-conotoxin MII as a new and selective antagonist for the neuronal nictotinic receptor alpha3 beta2 which is involved in nicotine addiction. The challenge and major goal of this project is to deliver alpha-conotoxin MII efficiently into the brain. A-Prof Toth has developed a novel drug-delivery system for the oral administration of drugs and peptides, which in their unmodified form are poorly absorbed or biologically unstable. In this project alpha-conotoxin MII will be combined with a specifically designed lipopolysaccharide delivery system . The delivery system can be specifically tailored to transport a wide variety of peptides through the different biological barriers. The peptides can be conjugated to the delivery system in such a way as to release the peptide after it has been absorbed (prodrug), or to form a biologically stable and active novel molecule. The outcomes of this work will include the first delivery system of nicotinic antagonists to the brain and new knowledge concerning the importance of the neuronal nictotinic receptor alpha3 beta2 in nicotine addiction.Read moreRead less