Fig 9. Frequency dependent increase in the atropine-resistant contractile response of the isolated detrusor strips in response to trains of 20 pulses at frequencies ranging from 0.25 to 40 Hz in the absence or following ATP-desensitisation (x3, 1mM ATP).

In the detrusor strips from drug naïve animals (a, c, d), ATP-desensitisation non-significantly inhibited peak contractile responses throughout the range of frequencies used (a) whereas in the strips obtained from MPTP-treated animals (b), the contractions were significantly decreased at frequencies beyond 4Hz. Time course of EFS-evoked contractile responses of detrusor strips from normal detrusor strips at 4 Hz (c) and 40 Hz (d) shows a greater inhibition of the primary peak at 4 and 40 Hz in the tissues obtained from MPTP-treated animals (e and f) compared to tissues from normal animals (c and d). Each data point represents mean ± sem (n = 4) * P<0.05, **P<0.005, ***P<0.001.