Joel Meehl
August 9, 2000
Abstract for Research Presentation to be given September 8, 2000
 

Smooth muscle is the type of muscle found in the walls of hollow internal organs.  It is involuntary and unstriated, and the least understood of the muscle types.  Smooth muscle can be activated by chemical agonists when they bind to receptors in the cells.  From these receptors messenger systems transfer the signal to the myosin molecules which cause the muscles to contract.  To better understand smooth muscle contraction, Dr. Eddinger's lab is investigating rabbit stomach smooth muscle single cells, and this investigation includes exploring the cells' pharmacological behavior.  These studies have found that phenylephrine activates the cells, and that phentolamine inhibits this activation.  This implies the presence of (x adenergic receptors in stomach smooth muscle cells, a phenomenon which has not been reported previously.  These newly discovered receptors, among other things, open up new possibilities for drugs to be used to treat gastric conditions and diseases.
 

Tissue studies must be done to confirm and validate the results of single cell studies.  Experiments were performed to test the response of rabbit stomach smooth muscle tissues to exposure to phenylephrine, the (x agonist, and phentolamine, the (x antagonist.  Strips of tissue were hung on an apparatus where their length could be varied and their force production measured.  The tissues were immersed in a bath of physiological salt solution (PSS) and the chemicals were added to this bath at varied concentrations.  It was confirmed that phenylephrine activates rabbit stomach smooth muscle tissues, and that phentolamine inhibits this activation.