Synaptic Integration And Plasticity In The Rat Piriform Cortex
Funder
National Health and Medical Research Council
Funding Amount
$250,500.00
Summary
The human cerebral cortex is the pinnacle of evolution. It is the most complex structure known, responsible for all of those skills - like language and reasoning - that make our species so remarkable. It is also a major site of many brain diseases, like schizophrenia and epilepsy. An understanding of how the cerebral cortex works would be a remarkable achievement, of immeasurable benefit to human health. How can one go about studying such a complex structure? The strategy taken in this project i ....The human cerebral cortex is the pinnacle of evolution. It is the most complex structure known, responsible for all of those skills - like language and reasoning - that make our species so remarkable. It is also a major site of many brain diseases, like schizophrenia and epilepsy. An understanding of how the cerebral cortex works would be a remarkable achievement, of immeasurable benefit to human health. How can one go about studying such a complex structure? The strategy taken in this project is to begin by studying one of the simplest regions of the cerebral cortex, the olfactory (or piriform) cortex. The olfactory cortex is an evolutionarily ancient region of cortex, with a simpler architecture than other cortical regions. Its task is to process the sense of smell, a primitive sense that is more elaborated in lower animals than in humans. The broad goal of our research is to understand, by studying the olfactory cortex of rats, how olfactory processing occurs at the level of nerve cells (neurons). We will use a number of powerful techniques - including microelectrode recording and laser microscopy - to measure the electrical properties of individual neurons. We will also study the synaptic connections between neurons, and how these connections change following memory-inducing stimuli. It is hoped that this work will shed light on how the healthy cortex is able to process and store information, and how brain diseases cause these functions to deteriorate.Read moreRead less
The Contributions Of Different Sources Of Calcium To The Induction Of Long Term Potentiation
Funder
National Health and Medical Research Council
Funding Amount
$267,750.00
Summary
When we make memories, we alter the strength of synaptic connections between nerve cells.These changes are particularly marked in the hippopcampus ; a region of the brain involved in the formation of memories. The strength of a synaptic connection is altered if it activates a neurone sufficiently to cause a rise in the level of calcium ions. Calcium can be derived from several sources within the neurone. This project aims to assess the relative importance of these different sources of calcium in ....When we make memories, we alter the strength of synaptic connections between nerve cells.These changes are particularly marked in the hippopcampus ; a region of the brain involved in the formation of memories. The strength of a synaptic connection is altered if it activates a neurone sufficiently to cause a rise in the level of calcium ions. Calcium can be derived from several sources within the neurone. This project aims to assess the relative importance of these different sources of calcium in inducing increases in synaptic strength.Read moreRead less
Obesity is an every increasing problem worldwide, with major risks for the development of associated cardivasular and type II diabetes related disorders. This research project will determine the underlying mechanisms of how specific receptors in the brain control energy metabolism, appetite and body fat accumulation. It will also determine how peripheral factors can influence this process. The outcome of this research should identify new targets and approaches to prevent and treat obesity and th ....Obesity is an every increasing problem worldwide, with major risks for the development of associated cardivasular and type II diabetes related disorders. This research project will determine the underlying mechanisms of how specific receptors in the brain control energy metabolism, appetite and body fat accumulation. It will also determine how peripheral factors can influence this process. The outcome of this research should identify new targets and approaches to prevent and treat obesity and the associated, type 2 diabetes and cardiovascular disorders.Read moreRead less
Synaptic Transmission In The Mammalian Central Nervous System
Funder
National Health and Medical Research Council
Funding Amount
$460,500.00
Summary
In order to properly understand the complex functions of the brain and the abnormalities underlying neurological disorders, we must understand how individual neurons communicate with each other. Communication occurs at specialized contacts, or synapses. An individual neuron may receive tens of thousands of synaptic contacts from hundreds or thousands of other neurons. Despite intensive investigation, the processes which regulate synaptic strength between central neurons are poorly understood. Th ....In order to properly understand the complex functions of the brain and the abnormalities underlying neurological disorders, we must understand how individual neurons communicate with each other. Communication occurs at specialized contacts, or synapses. An individual neuron may receive tens of thousands of synaptic contacts from hundreds or thousands of other neurons. Despite intensive investigation, the processes which regulate synaptic strength between central neurons are poorly understood. The overall aim of this proposal is to understand the basic mechanisms underlying synaptic transmission at excitatory and inhibitory synaptic connections in the mammalian brain. We will investigate specific synaptic connections in the central pathways of the auditory system, because our previous studies have demonstrated a number of key technical advantages in studying these synapses. We will use electrophysiological recording from synaptic terminals and neurons in isolated living slices of the brainstem of mice. We will use imaging techniques and electron-microscopy to examine the structural details of synaptic connections, as structure is thought to play a major role in determining the strength of synaptic transmission. We will also study the structural and functional properties of auditory synaptic connections in congenitally deaf animals. Our recent study comparing normal and congenitally deaf mice has already revealed significant differences. Our results will provide important insights in the regulation of synaptic strength in the central nervous system, and into the regulation of synaptic transmission at central synapses which have developed under conditions of abnormal sensory activation.Read moreRead less
I am a molecular physiologist investigating the structure and function of the inhibitory neurotransmitter glycine receptor (GlyR) and GABA type- A receptor (GABAAR) chloride channels. We are interested in understanding how these receptors open and close
Nerve cells have unique properties like their ability to put out axons that reach long distances from the cell body (differentiation), their ability to make contacts with other cells and initiate communication by the release of neurotransmitters from synaptic vesicles inside nerve endings (exocytosis) and the recycling of those synaptic vesicles (endocytosis). These events are mainly controlled by a large number of synapse-specific proteins, and partly regulated by a signalling molecule, cGMP, w ....Nerve cells have unique properties like their ability to put out axons that reach long distances from the cell body (differentiation), their ability to make contacts with other cells and initiate communication by the release of neurotransmitters from synaptic vesicles inside nerve endings (exocytosis) and the recycling of those synaptic vesicles (endocytosis). These events are mainly controlled by a large number of synapse-specific proteins, and partly regulated by a signalling molecule, cGMP, which mainly stimulates the enzyme PKG. In previous studies supported by the NHMRC we identified many proteins that are phosphorylated and activated by PKG. One of them, septin 3, is the focus of this proposal. We initially cloned septin 3 as a new member of a family of 10 genes that are essential for cell division. Some septins assemble as filaments that allow the two new daughter cells to finally separate. When the filament formation is perturbed certain septins end up in microscopic clumps that are found in the post-mortem brains of people affected by Alzheimer's disease, suggesting they might contribute to the disease. However, septin 3 is unlike most septins because it is a brain-specific septin, which we found in neurons and found to be highly concentrated in nerve terminals, locations not normally associated with cell division. The only other known brain-specific septin, CDCrel-1, regulates the protein machinery of exocytosis. We will examine the hypothesis that G-septin is also a regulator of synaptic vesicle endocytosis. We will determine whether septin represents a convergence point for cGMP signalling to control endocytosis. A better understanding of septin 3 and endocytosis is crucial to understanding brain disorders and ultimately developing better therapies.Read moreRead less
Secretion Of Alpha-synuclein: A Diagnostic Marker For Parkinsons Disease And A Clue To Its (patho)physiology
Funder
National Health and Medical Research Council
Funding Amount
$634,051.00
Summary
We have found that a protein, alpha-synuclein is low in people with Parkinson's Disease. We wish to see if this can be used as a diagnostic test for the condition. Alpha-Synuclein is thought to be important in causing Parkinson's Disease. We suspect that by finding out why less of this protein enters the blood stream in Parkinson's Disease, we may discover clues as to how alpha-synuclein causes problems in this condition.
Role Of G-septin And Its Phosphorylation By PKG In Nerve Terminals
Funder
National Health and Medical Research Council
Funding Amount
$363,055.00
Summary
Nerve cells have unique properties like their ability to put out axons that reach long distances from the cell body (differentiation), their ability to make contacts with other cells and initiate communication by the release of neurotransmitters from nerve endings (exocytosis). These events are partly controlled by a signalling molecule, cGMP, which mainly stimulates the enzyme PKG. However, it has been largely unknown how PKG takes the signalling further. In previous studies supported by the NH ....Nerve cells have unique properties like their ability to put out axons that reach long distances from the cell body (differentiation), their ability to make contacts with other cells and initiate communication by the release of neurotransmitters from nerve endings (exocytosis). These events are partly controlled by a signalling molecule, cGMP, which mainly stimulates the enzyme PKG. However, it has been largely unknown how PKG takes the signalling further. In previous studies supported by the NHMRC we identified 3 proteins that are phosphorylated and activated by PKG: SF1 controls the expression of genes in all cells; N-STOP stabilises the microtubule cytoskeleton to facilitate neuronal differentiation; and G-septin, which is the focus of this proposal. We cloned G-septin as the 8th member of a family of genes that are essential for cell division. Some septins assemble as filaments that allow the two new daughter cells to finally separate. When the filament formation is perturbed certain septins end up in microscopic clumps that are found in the post-mortem brains of people affected by Alzheimer's disease, suggesting they might contribute to the disease. However, G-septin is a brain-specific septin, which we found in neurons and in nerve terminals, locations not normally associated with cell division. The only other known brain-specific septin, CDCrel-1, was recently found to regulate the protein machinery of exocytosis, but is an unlikely target for cGMP. We will examine the hypothesis that G-septin is also a regulator of exocytosis. We will determine whether G-septin represents a convergence point for cGMP signalling to control exocytosis. A better understanding of G-septin and exocytosis is crucial to understanding brain disorders and ultimately developing better therapies.Read moreRead less
Neuropathways And Synaptic Adaptations Underlying Drug Addiction In Central Dopamine Systems
Funder
National Health and Medical Research Council
Funding Amount
$184,812.00
Summary
There is a rising trend in addiction to drugs, such as opioids (heroin) and stimulants (methamphetamine and ecstasy). A key feature of this addiction is intensified craving for the drug with repeated use. A major brain component thought to mediate drug-craving is the dopamine (DA) neurotransmitter system, consisting of cells in the midbrain that project nerve terminals to forebrain structures involved in reward-based learning. DA cells undergo long-term depression (LTD) and potentiation (LTP) of ....There is a rising trend in addiction to drugs, such as opioids (heroin) and stimulants (methamphetamine and ecstasy). A key feature of this addiction is intensified craving for the drug with repeated use. A major brain component thought to mediate drug-craving is the dopamine (DA) neurotransmitter system, consisting of cells in the midbrain that project nerve terminals to forebrain structures involved in reward-based learning. DA cells undergo long-term depression (LTD) and potentiation (LTP) of synaptic strength when excitatory inputs to DA cells are stimulated. These findings are important to drug addiction as amphetamine has been shown to block LTD and enhance LTP in brain slices of DA cells. Thus, changes in LTD and LTP by illicit drugs may underlie the conditions necessary for expression of drug-induced behavioural sensitisation, the best-accepted model of drug-craving in human addiction. To date, these studies have all been conducted in brain slices. Therefore, the functional importance of this synaptic plasticity in midbrain DA cells has yet to be shown in terms of changes in DA release in forebrain terminals in the living animal. For the first time we will address this issue by recording DA cell firing activity together with DA release using a newly developed technique that permits DA release to be monitored in the living brain in 'real-time' (100,000 samples-sec). This will allow us to identify the origin (cortical excitatory inputs) and receptor mechanisms that mediate LTP and LTD in DA cells and their effects on DA release. Recording DA cell activity with real-time measurement of DA release will promote a new cutting-edge technology to the Australian Neurosciences. These data will provide 'first of its kind' evidence of the functional anatomy and receptor mechanisms underlying synaptic plasticity in DA neurons associated with repeated drug use and ultimately enhance our basic understanding of the neural mechanisms of human drug addiction.Read moreRead less