Biology 325 Spring 2003 Visceral smooth muscle Analysis For each experimental manipulation calculate the frequency of muscle contraction and estimate relative changes in amplitude height of individual peaks from crest to trough and in overall muscle tonus the average level of sustained contraction represented by an increase or a decrease from a baseline Present these data in tabular form see Appendix I Make above comparisons between the times just before a manipulation to the periods following the treatment This is especially important since your baseline rate of contraction or control amplitude may have changed during the lab period A good way to present your observations would be to compute percentage changes in rate and amplitude and relative changes in tonus for each manipulation Analyzing the data from this set of experiments consists of observing the results of each manipulation and deducing some of the properties of the physiological system regulating gut activity Based on your results what are the effects of the sympathetic and parasympathetic nervous systems on visceral smooth muscle contraction What are the signaling mechanisms by which norepineprhine epinephrine and acetylcholine act on visceral smooth muscle What is a possible mechanism for KCl s effect if any What is the source for Ca in gut smooth muscle How did you prove this How does the Ca triggering mechanism differ between smooth and skeletal muscle in vertebrates We used atropine and AcH in combination to deduce the method of AcH action Using the results of your experiments are the receptors for ACH nicotinic or muscarinic type receptors Why Biology 325 Spring 2003 Appendix I Influences of extrinsic factors on contraction of visceral smooth muscle Treatment Baseline Epinephrine Acetylcholine KCl Ca free buffer Ca free buffer and AcH Ca free buffer AcH and CaCl2 Atropine sulfate Atropine sulfate and AcH Frequency of contraction contractions sec and change from baseline Amplitude of contractions grams and change from baseline Relative change in muscle tone grams and change from baseline