MECHANISMS OF TRANSMITTER SECRETION AT SYMPATHETIC NERVE VARICOSITIES
Funder
National Health and Medical Research Council
Funding Amount
$438,707.00
Summary
The mechanism by which quantal packets of transmitter are secreted from release sites called varicosities on sympathetic nerve terminals can now be taken to the molecular level, given the new techniques which we have introduced to solve this problem. There are two main facets to the problem. The first of these involves the question of how proteins involved in controlling the regulated secretion or exocytosis of the quantal packets of transmitter carry out this function. These proteins (syntaxin, ....The mechanism by which quantal packets of transmitter are secreted from release sites called varicosities on sympathetic nerve terminals can now be taken to the molecular level, given the new techniques which we have introduced to solve this problem. There are two main facets to the problem. The first of these involves the question of how proteins involved in controlling the regulated secretion or exocytosis of the quantal packets of transmitter carry out this function. These proteins (syntaxin, synaptobrevin, SNAP25 and synaptotagmin) together with a calcium channel are complexed with a docked synaptic vesicle containing a quantum of transmitter in a module of secretion appropriately called a secretosome. The leading questions here are to determine if only a single secretosome participates in transmitter release on the arrival of a nerve impulse, whether the number of these secretosomes in a varicosity determines its probability for secretion of a quantum, and fundamentally, how do the proteins within the secretosome cooperate to trigger exocytosis when there is sufficient calcium influx through the secretosome-associated calcium channel following the impulse. The other problem concerns the mechanism of removal of calcium from the varicosity once it has entered through the channels, This calcium can have considerable affects on the extent to which secretosomes participate in secretion with subsequent impulses. Furthermore, this influx of calcium can be modulated for subsequent impulses by transmitter released by the first impulse. The present research will solve these problems, providing a molecular description of secretion from single sympathetic varicosities.Read moreRead less
Identification And Function Of Kv7-M-channels In Axons Of Cortical Neurons
Funder
National Health and Medical Research Council
Funding Amount
$324,930.00
Summary
Membrane proteins permeable to potassium ions provide an important break during hyperexcitability of nerve cells in the brain. In this proposal I will study the function of a unique member of potassium channel protein (the M-channel) located at key regions of nerve cells; the axon. The results will provide important insights into the elementary steps of nerve cell excitability, and a better understanding of M-channel related diseases including neonatal epilepsies and chronic nerve pain.
Molecular Determinants Of Inhibitory Synaptic Function Studied Using Mutant And Transgenic Mice
Funder
National Health and Medical Research Council
Funding Amount
$496,500.00
Summary
Communication between nerve cells is the key to effective brain function and when disturbed, pathological states such as epilepsy, schizophrenia, fear and anxiety, spasticity and motor disorders ensue. This project is based on new data which suggests that the site of this communication, called the synapse, is a much more dynamic structure than previously thought. Based on our work to date, where we have demonstrated the recruitment of selected classes of neurotransmitter receptors into synapses, ....Communication between nerve cells is the key to effective brain function and when disturbed, pathological states such as epilepsy, schizophrenia, fear and anxiety, spasticity and motor disorders ensue. This project is based on new data which suggests that the site of this communication, called the synapse, is a much more dynamic structure than previously thought. Based on our work to date, where we have demonstrated the recruitment of selected classes of neurotransmitter receptors into synapses, our aim is to use a range of naturally occuring mice mutants, as well as transgenic mice to modulate the receptor levels and so to examine the role of synaptic function and synaptic dynamics. The outcomes of this project will provide fundamental new knnowledge aimed at understanding how communication in the nervous system works and may suggest ways in which modulation of this information flow could be used to treat disorders of brain function.Read moreRead less