Inhibitory effect of histamine on axonal transport in cultured mouse dorsal root ganglion neurons

Histamine is important in mediating peripheral sensory information such as inflammation, allergic hypersensitivity, and itch. In the present study. us ing video-enhanced microscopy, we investigated the effect of histamine on a xonal transport in cultured dorsal root ganglion (DRG) neurons of the mouse . Application of histamine (100 muM) reversibly reduced the number of parti cles transported within neurites in both anterograde and retrograde directi ons. The histamine H-1-receptor agonist 2-thiazolylethylamine (100 muM) and the H-3-receptor agonist R-alpha -methylhistamine (100 muM) also reduced a nterograde and retrograde axonal transport. whereas the histamine H-2-recep tor agonist dimaprit (100-1000 muM) had no effect. The effect or histamine was partially blocked by pretreatment with H-1-receptor antagonist pyrilami ne (1 muM) or the H-3-receptor antagonist thioperamide (1 muM). Pretreatmen t with a combination of pyrilamine (1 muM) and thioperamide (1 muM) complet ely blocked the response to histamine. The H-receptor antagonist cimetidine (1 muM) was ineffective. These results suggest that histamine inhibits axo nal transport of cultured mouse DRG neurons via the activation of H-1- and H-3-receptors. (C) 2001 Published by Elsevier Science Ireland Ltd.