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. using video-enhanced microscopy, we investigated the effect of histamine on axonal transport in cultured dorsal root ganglion (DRG) neurons of the mouse. Application of histamine (100 muM) reversibly reduced the number of particles transported within neurites in both anterograde and retrograde directions. The histamine H-1-receptor agonist 2-thiazolylethylamine (100 muM) and the H-3-receptor agonist R-alpha -methylhistamine (100 muM) also reduced anterograde and retrograde axonal transport. whereas the histamine H-2-receptor agonist dimaprit (100-1000 muM) had no effect. The effect or histamine was partially blocked by pretreatment with H-1-receptor antagonist pyrilamine (1 muM) or the H-3-receptor antagonist thioperamide (1 muM). Pretreatment with a combination of pyrilamine (1 muM) and thioperamide (1 muM) completely blocked the response to histamine. The H-receptor antagonist cimetidine (1 muM) was ineffective. These results suggest that histamine inhibits axonal transport of cultured mouse DRG neurons via the activation of H-1- and H-3-receptors. (C) 2001 Published by Elsevier Science Ireland Ltd.