Fig. 6.

Release of NE from cardiac synaptosomes during 30-min hypoxia. Bars (means ± S.E.M.) represent the hypoxia-induced increase in NE release above the normoxic basal level of 291 ± 24 pmol/mg protein (n = 14). Treatment with the selective histamine H₃-receptor agonist methimepip (1 nM; 12 min) reduces hypoxia-induced NE release, and this effect is blocked by a previous addition of the selective histamine H₃-receptor antagonist JNJ5207852 (30 nM; 12 min). PKCε blockade with εV_1–2 (1 μM; 20 min) and ALDH2 desensitization with GTN (2 μM; 30 min) each prevents the effect of methimepip (n = 5–16). ***, P < 0.001 versus hypoxia. ##, P < 0.005 versus methimepip. ###, P < 0.0005 versus methimepip by unpaired t test.