Figure 4.

Effect of pertussis toxin on sulprostone-induced inhibition of AVP-dependent cyclic AMP accumulation in the MTAL. MTAL samples microdissected from the same kidney were preincubated 6 h at 35°C in the control medium or in the presence of 500 ng ml⁻¹ PTX. The effect elicited by 1 μM sulprostone is expressed in percentage of the corresponding response to 10 nM AVP. Data are the mean values±s.e.mean calculated from four experiments performed in the presence of Ro 20-1724. ^*P<0.01–0.001 in individual experiments when compared to the corresponding response to AVP.