Effect of partial outlet obstruction on the myogenic response to field stimulation

1. Experimental studies of outlet obstruction have been performed on rats, rabbits, guinea pigs, cats, dogs and pigs. There is evidence that partial outlet obstruction can alter the membrane properties of the bladder smooth muscle and result in progressive denervation. The current studies were designed to evaluate the effects of moderate partial outlet obstruction on the response of isolated strips of rabbit bladder smooth muscle to field stimulation in the absence and presence of tetrodotoxin (TTX). 2. The results are as follows: In the absence of TTX, partial outlet obstruction resulted in a significant reduction in the neurogenic response at all frequencies. In the presence of 1 microM TTX, which caused maximal inhibition of the release of neurotransmitters, partial outlet obstruction caused a significant increase in the myogenic response to field stimulation. 3. These studies clearly demonstrate that partial outlet obstruction results both in a significant decrease in the neurogenic response of the obstructed bladder to field stimulation and in a significant increase in the myogenic component.