Fig. 7. Effects of buffer composition on the response of KCl (40 mmol l^–1) pre-contracted efferent branchial arteries to addition of 40 mmol l^–1 NH₄Cl and NH₄Cl washout (Wash) 30 min later. Buffer composition did not affect the KCl contraction nor the contraction accompanying NH₄Cl addition. *The contraction accompanying NH₄Cl washout was significantly weaker in Cortland than in Hepes buffer. Values are means ± s.e.m.; Hepes (N=4), Cortland (N=4).