A comparative study of electrical field stimulation of the guinea-pig, ferret and marmoset urinary bladder.

The spontaneous and electrically evoked activity was examined in guinea-pig, ferret and marmoset urinary bladder. Electrical field stimulation of detrusor strips in vitro induced a rapid, frequency-dependent contraction with a maximum response at 40 Hz. This contraction was partly decreased by either atropine (0.29 microM) or desensitisation to alpha, beta-methylene ATP (alpha, beta-MeATP) (5 microM), and was totally blocked by a combination of the two. Atropine blocked responses to carbachol (30 microM) but not to ATP (80 microM), whereas desensitisation to alpha, beta-MeATP blocked those to ATP but not to carbachol. The nature of the excitatory neurotransmission mechanism in the bladder of those species examined in the present experiments was shown to be similar to that of other species described previously.