The urethra generates spontaneous myogenic tone which is thought to play a role in maintaining urinary continence. However, the mechanisms responsible for the generation of this tone are poorly understood.
One of the main goals of our research is to examine what mechanisms are responsible for the generation of this tone. Our research has demonstrated that sheep urethral myocytes express large chloride currents when studied under voltage clamp using the perforated patch configuration of the patch clamp technique (see figure 1 below).
(Figure 1. Calcium activated chloride currents in sheep urethral smooth muscle.)
In approximately 10% of these cells spontaneous activity was observed. A typical example of this activity is shown in figure 2. Theslow waves were abolished by nifedipine and unmasked spontaneous transient depolarisations which we believe underlie spontaneous activity in the urethra.
(Figure 2. Nifedipine unmasks STDs in urethral myocytes)
We are currently examining the mechanisms underlying the generation of these STDs in urethral cells using a combination of electrophysiological and cell imaging techniques.