Do differences in innervation result in different post-synaptic responses to exogenous agonists?

1. The pharmacological reactivity of the epididymal and prostatic portions of the rat vas deferens to BaCl2, phenylephrine and carbachol were recorded by isometric and isotonic technique. 2. The maximum response induced by the three agonists were similar at the epidiymal end, while at the prostatic portion phenylephrine produced a response 80% lower than that of barium and carbachol. 3. The pD2 value to agonists and the sensitivity to calcium channel blockers were lower at the prostatic end. 4. The data suggest that not only the pharmacological reactivity of the prostatic and epididymal portions differs, but also that the activity of the prostatic portion is much more reduced to alpha 1-agonists.