HISTAMINE MODULATES NMDA-DEPENDENT SWELLING IN THE NEOSTRIATUM

In the present study, infrared differential interference contrast vide omicroscopy was used to examine the effect of histamine on N-methyl-D- aspartate-induced swelling in neostriatal neurons in a brain slice pre paration. Histamine caused a concentration-dependent increase in swell ing evoked by N-methyl-D-aspartate. By itself, histamine did not cause swelling. Electrical stimulation also caused N-methyl-D-aspartate-dep endent swelling which was enhanced by histamine. in addition, histamin e was found to enhance N-methyl-D-aspartate-induced swelling from post natal day 7 to 28 but not at postnatal day 3. Finally, this histamine- induced enhancement was prevented by treatment with either the H-2 rec eptor antagonist cimetidine or with the potassium channel blocker tetr aethylammonium chloride. Overall, these findings suggest that histamin e modulates N-methyl-D-aspartate receptor function in the neostriatum through a H-2 receptor-mediated regulation of potassium channels. (C) 1997 Elsevier Science B.V.