Voltage sensitivities and deactivation kinetics of histamine H3 and H4 receptors

► We study voltage sensitivity and deactivation rates at histamine H3 and H4 receptors. ► Histamine potency in a channel activation assay is decreased by depolarization. ► The potency decrease is more pronounced at hH3445 than at hH3365 and H4 receptors. ► Rates of deactivation upon agonist washout differ between the histamine receptors. ► The hH3365 receptor deactivates about 5 times slower than the hH3445 receptor.