[Inhibition of 8-OH-DPAT on spontaneous unit discharges of 5-hydroxytryptamine inhibitory unit in rat primary somatosensory cortex].

Aim: To investigate the effect of 5-hydroxytryptamine(5-HT) on spont a neous unit discharges of primary somatosensory cortex (SI-SUD) and the role of 5-HT_ 1A receptor in 5-HT inhibitory effect on SI-SUD in rat. Met hods: The SI-SUD was recorded before and during microiontophoresis of 5-HT and 8-OH-DPAT(the selective agonist for 5-HT_ 1A receptor. The chan ges of mean of inter-spike interval(MISI) of SI-SUD were analysed and handled with the statistics. Results: ① Effects of 5-HT on SI-SUD may be inhibitory(48/96), excitatory(26/96) or non-responsive(22/96), and the major effect is inhibitory. ②In 20 of 5-HT inhibited units, 17 are also inhibi ted with microiontophoresis of 8-OH-DPAT, but 3 have no obvious response to 8 -OH-DPAT. Conclusion: The major effect of 5-HT on SI-SUD is inhibitory. In majority of 5-HT inhibited units, 5-HT_ 1A receptor may be existence,which may involve in the inhibition of 5-HT on SI-SUD.