Fig 2. Effects of adrenoceptor antagonists on the NA-induced suppression of capsaicin currents.

(A) Typical control responses to NA (1 pM) in the absence of antagonists are shown (Same traces as Fig 1B). (B-D) Prazosin (10 nM), yohimbine (10 nM) and propranolol (10 nM) were applied in combination with NA (1 pM) in the same protocol as A. Dashed lines in panels A-D indicate zero current level. (E) The relative peak amplitudes of capsaicin currents by the second stimulation compared to those by the first stimulation in each neuron are shown (2nd/1st response). The columns and vertical bars indicate the mean ± SEM (n = 5, 8, 5, 6 and 5 from the left). * P < 0.05 against the control data in the absence of NA; † P < 0.05, †† P < 0.01 against the control data in the absence of antagonists.