Histamine promotes motor balance and motor coordination in accelerating rota-rod via H2 receptors in the cerebellar interpositus nuclei. (A) Motor performances of rats microinjected with normal saline, GABA, histamine, ranitidine (antagonist for H2 receptor) and triprolidine (antagonist for H1 receptor) in accelerating rota-rod. (B) Reversal effect of histamine on ranitidine-injected rats. *P < 0.05; **P < 0.01. Modified from Song et al., Neuroscience, 140:33–43, 2006.