Fig. 3. The effect of cholinergic and nitrergic antagonists.

The effect of cholinergic and nitrergic antagonists alone (a) and following subsequent veratridine-induced mucosal responses (b) on the change in I_SC levels in transverse colon from untreated or MPTP-treated marmosets. Tissues were treated with either atropine plus hexamethonium (Atr+Hex) alone, L-NNA alone or Atr + Hex + L-NNA (a, b). Subsequent veratridine-induced changes in I_SC are divided into an initial 1°, and a slower 2° component after each pre-treatment (b). Values are change in I_SC (mean±SEM). Replicates are shown in parentheses. ^*P ≤ 0.05 compared to vehicle treatment (ANOVA and Dunnett’s test).