<prompt> Ca2 Channel blockers would have a significant effect on muscle function inSkeletal muscleSmooth muscleBoth the aboveNeither  <response>: The calcium-channel blockers represent a group of organic chemical structures that share the ability to inhibit Ca2 entry into excitable cells. ... Thus, calcium-channel blockers are smooth-muscle dilators and have a negative inotropic effect on the working myocardial cells of the atria and ventricles Ref guyton and hall textbook of medical physiology 12e pg 73 