Supplementary Figure 5: K+ concentrations lower than 10 mM also dilated upstream arterioles when applied onto capillaries, with a threshold for activation between 6 and 7 mM K+ followed by moderately graded responses between 7 and 10 mM.
From: Capillary K+-sensing initiates retrograde hyperpolarization to increase local cerebral blood flow
(A) Typical intraluminal arteriolar diameter at Zone 1, located at the point from which the primary capillary initially branches out, during stimulation of attached downstream capillaries with 6, 7, 8, 9 and 10 mM K+. (B) Summary data showing peak diameter changes in Zone 1 in response to the different K+ concentrations (n = 5 preparations from 5 mice; 6 mM K+ vs 7 mM K+: ***P = 0.0005, (t5 = 10.48); 7 mM K+ vs 8 mM K+: *P = 0.0385, (t5 = 3.038); 8 mM K+ vs 9 mM K+: *P = 0.0330, (t5 = 3.196); 9 mM K+ vs 10 mM K+: P = 0.0538, (t5 = 2,706), paired Student’s t-test). All error bars represent s.e.m.
