SEMINAR: Mechanisms responsible for 'catch-like' force enhancement in skeletal muscle

The Seminar: Some forms of smooth muscle show a property known as 'catch', where force production is maintained even though intracellular Ca2+ (the trigger for muscle contraction) drops back to very low levels. Skeletal muscle has also been reported to display a 'catch-like' enhanced contractile response when activated by two high frequency nerve impulses (doublet stimulation) at the start of a nerve impulse train. This 'catch-like' phenomenon is reported to result from a brief, greater than normal increase in intracellular Ca2+ after doublet stimulation, which initiates a larger, more rapidly rising and more prolonged force response. However, these conclusions concerning doublet-induced Ca2+ release may be based on studies using inappropriate methodology to measure intracellular Ca2+. This seminar will outline recent results re-examining doublet-induced Ca2+ release in skeletal muscle and its effects on force production, and review how these results reshape our understanding of the mechanisms responsible for 'catch-like' force production in skeletal muscle.

The Speaker: Tony was awarded his PhD from La Trobe University, Melbourne in 1993. He then spent the next two years with the Muscular Dystrophy Association (USA) as a Research Fellow in the Department of Physiology & Biophysics at the University of Texas, Medical Branch. Following on from this appointment in 1995 through to 1997 he was a NH&MRC Research Officer with the School of Physiology and Pharmacology, University of New South Wales, Sydney.