Effects of phenylephrine in single isolated smooth muscle cells of rabbit and guinea pig taenia caeci.

Spontaneous transient and evoked outward currents were studied using the whole cell patch-clamp technique with freshly dispersed smooth muscle cells isolated from rabbit and guinea pig taenia caeci. Phenylephrine induced a low amplitude sustained outward current in both tissues. Simultaneously, the frequency and amplitude of spontaneous transient outward currents were increased. However, there were differences between the effects of phenylephrine on the evoked outward currents recorded from smooth muscle cells of rabbit (reduction) and guinea pig (enhancement) taenia caeci.