The H3 receptor agonist exhibits all of the following actions except
H3 receptors act as presynaptic receptors and decrease the release of histamine and other neurotransmitters. this antagonize H1 mediated wakefulness and bronchoconstriction. these also decrease gastrin release and produced negative chronotropic effect inverse agonist and H3 receptor(tiprolisant) is proved for narcolepsy. Refer KDT 6/e p153
Inhibition of H1 receptors induced wakefulness
Increase in H1 mediated gastric secretion
Inhibition of H1 mediated bronchoconstriction
Negative chronotropic effect on atria
Autacoids