PhD Candidate
The University of Western Australia
Department
Deparment of
Physiology
Skeletal muscle Physiology: Development, Growth and Disease
During skeletal muscle development, whether in the foetus or after muscle injury, non-contractile mononucleated muscle precursor cells multiply and fuse to form single multinucleated skeletal muscle myotubes. The myotubes grow in size and eventually develop into adult skeletal muscle fibres. During this time, the myotubes also gradually gain the ability to contract in response to electrical stimulation. Collectively, the events that link membrane excitation to contraction are known as excitation-contraction coupling. In this laboratory, we use skeletal muscle developing in culture as a model of muscle development We utilise fluorescent ion indicators and electrophysiological techniques to examine the events and mechanisms by which excitation-contraction coupling forms during the development of skeletal muscle.
We are also interested in the mechanisms responsible for the muscle wasting observed in two lethal forms of muscular dystrophy, ie Duchenne muscular dystrophy and congenital muscular dystrophy. In both these inherited myopathies, the genetic defect results in the absence of important proteins at the level of the surface membrane system. Ultimately, the absence of these proteins leads to muscle cell death due an overload of calcium ions, the concentration of which is kept under tight control in normal, healthy skeletal muscle. Presently, we are investigating novel mechanisms whereby the absence of these specific proteins might lead to abnormal levels of Ca2+influx in dystrophic muscle and consequently, skeletal muscle cell death.
In relation to our work on muscular dystrophy, we are also interested in factors that stimulate skeletal muscle growth. Recently, we have undertaken a study into the cellular mechanisms of action of the anabolic agent clenbuterol, a b -agonist often abused in athletic and bodybuilding circles. Clenbuterol can increase muscle bulk in animals by up to 15 % in 2 weeks in the absence of excercise, while at the same time reducing body fat. This drug is of interest because of its potential clinical importance as a treatment of muscle wastage. For example, in the elderly after an injury such as a broken hip, many people do not recover mobility even though the bones heal satisfactorily. This is primarily because the skeleletal muscle atrophy that occurs in old patients during immobilisation is presently irreversible. Our ongoing studies, using the skinned fibre technique (where the muscle membrane from the fibres is removed, allowing access to the intracellular space), show that clenbuterol, has other important effects on skeletal muscle physiology, not related to its b -adrenergic action.
Peking University, Beijing, P.R. CHINA
July 1st, 1998, Bachelor of Sciences in Physiology &
Biophysics
The University of Western Australia
March 1st, 1999, comment PhD studies in Physiology
Street address
MR. Renzhi Han, Department of Physiology, The University of
Western Australia, Nedlands, WA 6907, Australia
Electronic mail address
[email protected]
Web address
http://campus.fortunecity.com/belhaven/876
ICQ number
37077444
Office phone
+61 8 93807859
FAX number
+1 209 3155086 or +61 8 93801025
This is my first homepage. My main goal is to build a friendly bridge between China and Australia, especially for the Chinese students who want to learn more about Australian Nature and Education and for the Australian students who want to learn more about Chinese Culture. Of course, this is just a try. Your excellent ideas and suggestions will be greatly appreciated. In addition, I am a PhD student majoring in Biomedical Sciences, if you are interested in talking about the research of Calcium and it's binding proteins in human and animals, you are welcome. Please send me mail telling me what you think about this page and how I might improve it.